Klemen

you can try MashAI from Asus, prob other companies have sth similar like access points, but here you have multiple routers connect between each other that serve as a boost. CAT7 cable would support higher speeds with the router that can take advantage of that, hence even CAT6a would be enough, but those are only tools that can support those speeds. The one who carries that speed is coming from your ISP or ISR device. In orther to get higher speeds you would have to talk with ISP and set or unlock higher speeds which costs more money or change a subscription package you are running on. Usually at homes you get around 1Gb as a standard or maximum somewhere, to get more than that it would cost a lot more. At least that's to my understanding. 
 
If you are paying fix amount of money for 700Mb/s connection, then no router or cable will increase that speed. Usually at homes if they have speed like that they can go up to 1Gb since they have router and cables that support maximum of that. 
 
It would be different however if you said you have subs for 2.5Gb and you have only 700Mb/s. then that would just call for an upgrade of either cable or router of both. 
But what you can achieve with better router is higher WiFi speeds.   
 

I have read that you can turn off using the account only _after_ you created it and tied the device to it, and when you have disabled using that you can't transfer ownership of the device anymore.  Besides all others issues with that, it means you didn't buy the device but only rented it.  Even when it's a one-time payment, it means you don't own your hardware.  And you don't know if Ubiquity suddenly decides that using the account all the time is required and that users have to pay some subscription fee.
 
And what about your privacy?  It's not in any way where, how, when, for what, and so on, Ubiquitys business what you do with your hardware.  But that you can't use "your" hardware without notifying them is a massive rape of your privacy.
That isn't the point.  An UDM isn't their so-called cloud key.  It is a device that you pay for and yet it isn't yours as they keep control over it, not you, and it rapes your privacy.  It is an entirely non-free device.  That is not a device which I would want to allow to control my internet access, or anything else.
 
Besides, Ubiquity has always been extremely bad on documentation, and that didn't really change, though they tried to improve the documentation over time (but it still sucks).  That means you have to keep asking questions on their forum and hope that maybe you get answers eventually.  Many times you don't and that means you simply can't do what you need to.
 
For someone like the OP who seems to be interested in learning, I can point to routers and switches HP makes (or used to make) because they come with excellent documentation.  The documentation is so good that you can learn from it.  Compared to Procurve and Aruba switches, Ubiquitys EdgeMAX switches and routers are total crap because their configuration and administration is more like a nightmare than anything else, whereas Procurves and Arubas are extremely easy and a sweet dream to handle.  The only thing that does speak for Ubiquity is their relatively low price and that their hardware has advantages in that it usually doesn't run its fans and consumes less power than the HP (relatively old) switches.  HP may have improved on power consumption, I don't know.  HP has a lifetime warrany on some products, and they do replace your 15 year old switch, when broken, under warranty, even though you bought it used off ebay for 20 with a practically new one, and they even pay for the shipping.  As to Ubiquitys Unifi switches, you can't manage them without all the infrastructure and their management software running somewhere and accessible, and that makes their switches practically useless.  I need to be able to manage a switch by itself, especially since switches are infrastructure devices that need to work and do their part before the infrastructure is in place.  OTOH, HP has gone bad with their support because you have a hard time to get firmware updates without a support contract, which is something you don't get.  Cisco is much worse, so never buy anything from Cisco (or linksys).  That has been an advantage with Ubiquity as they don't give you trouble with firmware, but when they discontinue the EdgeMAX products, they will make no longer make any relevant products.
 
Having that said, I'm not entirely happy with OPNsense or PFsense because neither support zone base firewalls.  Yet that is someting I can live with, and what other option is there short of installing Fedora or the like and making your owner router with that.  I've done that 20 years ago with Debian, and it has become easier since.  If you really want to learn, make your own firewall from scratch with iptables and go from there.
 

Bear in mind there is very little WiFi 6e hardware right now, I'd not worry about that and just get a WiFi 6e Access Point later on once they are available.  I'm personally waiting on Zyxel to come out with one as while it will cost as a much as a router, them being business APs they are far more reliable than consumer equipment and built to last.
 
As for VPNs, if you do decide to use one bear in mind you're probably not going to get more than 300Mbit or so out of one, as its not cost effective for them to offer faster due to how few customers they can service per server at those speeds, particularly if they are using OpenVPN.

I just go by the laws of physics. But if you end up doing some form of testing I would advise you to post your results. Unfourtrinally I haven't seen too much WiFi 6E gear yet. I also haven't seen any testing from any of the Youtubers I normally watch. 

Your teacher is an idiot.
A router is a device through which different devices and subnets can communicate.
A switch moves packets within the same VLAN/broadcast domain (without getting into mutli-layer switches). A switch moves packets in and out too.

Most of the ISP routers Ive used have a good amount of settings, they let you do things like port forwarding, change DHCP and DNS settings and toehrs. 
 
Not really for average home use. The defaults are pretty good. 
 
Apps recording info about isn't affected by the router, the router just passes it between your pc and their servers, you can't really easily block it on a router as its all encrypted anyways.
 
You can setup something like a pi-hole for a dns filter that can help some, but most privacy improvements are from using different services and settings, not by a different router or VPN.

you would set these up on a computer to work as a router. Normally a seperate pc.
 
Id stay away from a VPN here with your use case, it won't really help, and now the VPN provider and their ISP can snoop on your traffic.
 
Normally open source = more secure, but really depends.

Probably that either the RAM or RAM controller need a bit higher voltage to run at this freq.

I'd like a small something to what @Alexeygridnev1993said in his last para, the DE doesn't matter much when you're trying to learn and as you continue using it, there will be itch to explore other distros and embrace that, as you keep trying others you'll eventually also find which distro and DE would be most suitable for your taste.

It's easy to get confused by a plethora or distros, but, essentially, most distros can be divided into four big groups: Debian-based (including all forks of Ubuntu, Zorin OS, PopOS, Elementary OS, etc.), Arch-based (Arch, Manjaro), RHEL-based (RHEL, Fedora, CentOS), and Gentoo-based. There are distros which do not fit any of the four above-mentioned groups (like Clear Linux from Intel) but those are exceptions. Within those groups, package managers and general logic of how they work is pretty similar, so, it will be easier to move from one distro to another within a given group, and harder to switch between groups.
 
Debian-based distros (especially Ubuntu and its derivatives) are the most widespread as desktop systems, and Ubuntu is increasingly important in servers, so, I would recommend to start from any of Ubuntu derivatives; any skills you learn there won't be useless.
 
What desktop environment you run (GNOME, KDE, Xfce, LXQt, or others) is pretty much irrelevant for learning Linux, desktop environment in Linux is just a package which can be installed and removed (i.e. you can get a standard Ubuntu which uses GNOME, remove GNOME and install KDE, no problem). So, desktop environment is just a matter of personal aesthetic preference and of your hardware (i.e. GNOME is much more resource-demanding than LXQt).

might be worth turning render resolution down a little might look trash though. Your friend may just have different settings set up auto.
 
Turn off settings like Ambient Occlusion that affect gpu heavily.

Current/Bleeding Edge        Debian Testing/Sid
 
Like to 'Tinker'                    Debian Sid
 
Rock Solid Stable                 Debian Stable
 
 
 

Then something based on Arch is your best bet. Though probably not vanilla Arch, as it's a command-line manual installation and generally the progression is "Ubuntu -> Manjaro/Endeavour/Garuda/something else Arch-based -> 'I've been on Linux for two months so I think I'm ready to install Arch now'"
 
But installing and maintaining a vanilla Arch install is the best way to learn Linux by far. I pretty much had the above progression (but add in like 20 other distros because I wanted to try them all) and I've been daily driving Arch ever since (though I also keep a Manjaro and Pop OS partition alongside my main Arch one). 
 
But yeah, something based on Arch is what you want. It's got way more software easily available than Debian Sid/Solus/other rolling-release distributions, it's got the Arch Wiki which is the best resource there is (hands down), Arch-based distros are very quickly catching up to Ubuntu-based ones in popularity so you have a large user base from which to pull support, if you game, they're the best family for gaming, the list goes on. Oh and another huge one is support for new hardware. I bought both the RX 5600 XT and the RTX 3090 on their respective launch days, and Arch-based distros are the only ones that handled the AMD card well (without heavy manual intervention) and the only ones that could even run the RTX 3090, because of their rolling release nature, and the fact that Arch doesn't require GPU drivers to install (because it's command line only during installation, there's no GUI until after you've installed the system and GPU drivers). So where Ubuntu and it's derivatives had Nvidia drivers too out of date to support the 3090, Arch had the official RTX 3090 release drivers available on day one. 
 
And once you're able to handle vanilla Arch, it's by far your best bet. As I said you install it from the command line and so you only install exactly what you want, you completely customize it from the ground up, basically it's like Linux From Scratch only intended for actual use and not as a project. 

What @gardotd426 said is also true for Gentoo.

No. Definitely, definitely not. 
 
It has almost no software compared to other desktop Linux distros, and it's 100% not intended for general use, it's intended for a very, very specific use-case and if you don't know what it's intended for, then you don't need it. Clear Linux is highly optimized for the Cloud, and of all its uses, a desktop PC is like, last on the list (or really not even on the list). 
 
The best Linux distro (for YOU, because there's no such thing as "the best Linux distro") is whichever one fits your style. Do you prefer bleeding edge, or boring and old/stable? Do you like to tinker? etc. What do you plan to use the computer for? The answer to your question depends on the answers to all of mine. 

@Klemen--
Slackware and Gentoo are source-based distros, meaning the user compiles individual software packages.  See this older 2011 post (tinyTux, post #3) as an explanation of its advantages.  And this even older description of its disadvantages versus binary packages in say, Debian.
 
@Nayr438stated dome differences between the three basic distros mentioned (Gentoo, Slackware and Debian) but to me the single biggest difference bewteen distro families is Package Management or the means by which a distro draws on its repositories and presents a software package for installation by the user.  See Package Managers.
 
With all due respect for BSD (which is worth exploring to better round out your knowledge of UNIX-like OSes), the OP is asking about Linux. 
 
No, one cannot necessarily go back and forth readily between distro families (Redhat is another, albeit an enterprise distro) .  The exception is between Debian and Ubuntu.  The latter was derived from the former and is therefore very similar, but not identical to its parent, Debian.   APT and DPKG are the similarity.  These are favored package mangers used by both. 
 
After giving it some thought (and knowing peer pressure to use the most popular distro) I'd seriously suggest beginning with a non-specialized true Debian distro such as MX.  There are others, of course, but despite a popular misconception commonly in use, Ubutu-based DOES NOT EQUAL Debian-based.
 
Starting with a true Debian will give the background in binaries and allow easy crossover to 'buntu-based distros like Mint, elementary, zorin,  and too many others to list.  And please do not be tempted to get into specialty distros like pop!OS and Kali -- they are not for beginners who want to go in the direction OP has stated.  Debian also arguably  has the largest software selection in its repositories of any GNU/Linux distribution out there.
 
And, DO LEARN the command line usage of APT.
Here is one example of a Linux Command Line Cheat Sheet
 
It is of paramount importance to learn basic commands.  Those who do not do so are lazy and will never be able to  fully take advantage of the innate power of GNU/Linux.
 
NOTE:  Sabayon is a beginner-friendly Gentoo-based distro using the pakage manager portage,  which requires a fast internet connection to facilitate compiling.   And, please DO download the PDF file Rute Linux Tutorial and Exposition listed in the link above, for a completer reference.
 
HAPPY HOLIDAYS TO ALL!
 

If you want to get a job working in Linux there are three distros you should get used to (in order from most popular to least popular in the enterprise)
 
RHEL (Red Hat / CentOS - rocky linux ) Ubuntu OpenSuse  
I would suggest just learning Linux how you want to learn it, and not focusing on a specific OS because it's used in the enterprise.  All distros are quite similar, and knowing the core of how Linux works is more important than knowing some tools
 
The main thing you should work toward if you want to work in Linux is getting Red Hat certifications.  RHCSA, RHCE.  If you're brand new to Linux, don't worry about Red Hat just focus on learning Linux and having fun. 
 
Getting a cloud certification is useful as well if you want to work in Linux, since nowadays a lot of Linux Jobs are DevOps related.  You'll be developing automation workflows, implementing CI/CD pipelines and working on platforms.  Even if they're on-prem having a cloud certification helps because a lot of the knowledge will carry across environments. 

The biggest differences between Distributions will be the Default Desktop Environment, repositories, package manager (different commands and UI if applicable), age of packages, amount of packages in the repo, and how dependencies are handled. Gentoo itself is a source based distribution, so everything is compiled from source, at least to my knowledge.
In terms of dependencies, most distributions handle this for you, Arch based distros such as Manjaro however do not, it leaves the choice up to you on whether you want them or not.
The big 2 Desktop Environments are KDE Plasma and GNOME ( Most Common, with variations ), however there are several others, you can view a list of the more common choices here https://wiki.archlinux.org/index.php/desktop_environment Regardless of Distribution, you may find the Arch wiki fairly informative as well.
 
If you decide to distro hop, I would create a separate partition or use a spare drive to store anything you deem important. While you can mount your /home directory to a partition through fstab, If you change desktop environments or even versions of desktop environments, it can cause various issues. So I would expect to start from scratch each time.

100% agree. The BSDs are so much nicer. I'm so fed up with Linux reinventing how I'm supposed to connect to the network every week and having 19 ways of installing packages on the same system.

I find different Linux systems very foreign to each other. There are different firewalls (iptables, ufw on Debian, firewalld on CentOS for example). There are tons of different ways of managing network connections (NetworkManager, netplan, etc). There are different init systems (systemd, openrc, runit), which means different ways of starting services. There are different package managers (yum, apt, pacman, dnf, snap, and tons of others).
 
There are different graphical environments and window managers too. Most people think of these as differences but they don't matter; you can install any of them anywhere. It's much harder to change the package manager or init system.

Try Gentoo. You'll have to learn a lot to make it even run. (And it is rather good.)
 
You should have asked me. I, personally, find Linux too incoherent (of course, as the kernel, the userland and the desktop come from different teams, unlike Solaris and the BSDs where everything is a part of the base system), it is relatively unreliable (compared to OpenBSD) and the community can be weird. But it cannot be wrong to try as many systems as you can find. Just make sure that you don't focus too much on a very narrow selection...
 
No.

Best for learning Linux: Slackware, Gentoo, or Arch
 
Best for out of the box general desktop/laptop usage: MX Linux
 
Most applicable to a sysadmin career: Red Hat, Debian
 
GNU/Linux was originally intended to be a freely licensed clone of Unix, but at this point has sort of morphed into its own category IMHO. Any Linux system with systemd is radically different from Unix in both philosophy, and the overall "feel" of it. For learning, I'd strongly recommend also running a non-Linux, actual Unix-derived system like one of the BSDs or a Solaris derivative like OmniOS. It will put any Linux experience into a better perspective, and you will see why things are done a certain way in various systems and have a reference point for comparison.

Have you looked into Gentoo, perhaps the most customizable distro; or considered Slackware, the most UNIX-like and perhaps the most stable distro, once set up as a server? 
 
I was at it quite a while before going to Slackware stable.  It was a goal because, originally, I wanted to learn UNIX but solaris and oracle legal bs got in the way.  Which brings me to Clear OS, the Intel-designed distro which, not surprisingly, works the best with Intel hardware.
 
I shy away from Oracle because of its M$-like philosophy when taking oveer Sun (and Sun's ZFS file system).   Also, Clear OS apparently is not out of alfa even though it is claimed to be.  Bottom line it is unproven in extensivity and could therefore be considered a specialty distro, much like Kali. 
 
Maybe keep it in the background as a goal while learning the basics and it may be ready when you are. 
 
Hardware-wise, i THINK YOU HAVE NO LIMITAITONS.  Sabayon could be what you are looking for.

I'd say that in IT it doesn't matter which Linux distro you use, as long as you can use the CLI.
If any distro matters the most for IT, it'd be Ubuntu of course. But I guess that's a little boring for personal use.
 
I personally don't even use Linux as my prefered OS and instead use Windows and yet I got a good job in IT working with Linux machines. 

clear os is a speica distro for performance, id stay away from it for most uses.
 
Probalby learn ubuntu/ centos, everything else is pretty simmilar.