Nocte

If you are getting scammed you shouldn’t pay for anything?

This could be a starting point for you. Play around with the parts as you see fit for your specific use-case.
 
PCPartPicker Part List
CPU: AMD Ryzen 7 7800X3D 4.2 GHz 8-Core Processor  ($499.95 @ shopRBC)
CPU Cooler: be quiet! Dark Rock Pro 4 50.5 CFM CPU Cooler  ($104.99 @ Canada Computers)
Motherboard: MSI B650 GAMING PLUS WIFI ATX AM5 Motherboard  ($209.99 @ Amazon Canada)
Memory: ADATA XPG Lancer Blade 32 GB (2 x 16 GB) DDR5-6000 CL30 Memory  ($119.99 @ Canada Computers)
Storage: Samsung 980 Pro 1 TB M.2-2280 PCIe 4.0 X4 NVME Solid State Drive  ($119.98 @ Memory Express)
Video Card: Gigabyte WINDFORCE OC GeForce RTX 4070 12 GB Video Card  ($699.00 @ Canada Computers)
Case: Corsair 4000D Airflow ATX Mid Tower Case  ($104.99 @ Amazon Canada)
Power Supply: Corsair RM750e (2023) 750 W 80+ Gold Certified Fully Modular ATX Power Supply  ($137.50 @ Vuugo)
Total: $1996.39
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2023-12-24 21:22 EST-0500

I would go with the 7800X3D:
It consumes WAY less power than the 14700k (up to 3 times less at max load) It provides better gaming performance than the 14700k in most (all?) games (e.g. 7800X3D pulls 200+ fps in Cyberpunk @ 1080p vs. ~165 of the 14700k) 7800X3D is cheaper, allowing you to go DDR5 without increasing the overall build price (as shown in your partpicker) Maybe this video will help you making an informed decision:
 

Given your budget I would honestly go with the 7950X3D...
Drop the PCIe 5.0 overpriced SSDs and go with PCIe 4.0 ones (unless you can actually saturate 4.0 - I doubt it).
The SSDs I picked do not show up with a price on PCPP, but you can find them on Amazon.de.
 
3235€ - https://de.pcpartpicker.com/list/NY2YRK

Is it a clean Windows install? How did you manage driver installation/change?

Given your budget I would honestly go with the 7950X3D...
Drop the PCIe 5.0 overpriced SSDs and go with PCIe 4.0 ones (unless you can actually saturate 4.0 - I doubt it).
The SSDs I picked do not show up with a price on PCPP, but you can find them on Amazon.de.
 
3235€ - https://de.pcpartpicker.com/list/NY2YRK

That's a bit extreme. Just flash the correct bios and enjoy the system. It isn't difficult. You have bios flashback.

You can’t build a gaming pc with £100, not even with used parts unless some core components are donated to you. 

If the source is Stereo, you'll get Stereo output. I don't know what this "7.1 Surround Sound Box" is, or these amps. Are you just trying to force a 2-channel audio source through all the speakers? Surround sound for PC's is effectively dead these days so I'm surprised you went this route. 

Please don't update it from Windows. Update it with a USB stick from within the BIOS.

Not all motherboards are ABAB for RAM slots (although most are). Make sure it's not AABB.

AM4 only supports DDR4, whereas AM5 (Ryzen 7000+) only supports DDR5.
You therefore need to know what CPU you have or you will be buying something that might not be compatible with your system.

It looks fine from the picture you posted. It would help if the picture was taken from a more vertical angle. 
 
If the lock clicked and the PC is working without hiccups I wouldn’t worry about it. 

G4560 is a better CPU and has better other components. 

Learn the basics and then practice by working on your own projects, try to find something you wish it would be automated and create a program for it. 
 
You will start facing challenges on how to do x which is part of achieving y, find resources and eventually you will take in more and more knowledge. 
 
There is no beginner to master guide for anything. Being a master means having implicit/tacit knowledge. Guides offer you explicit knowledge, which only helps to a certain extent. 

Can't you just put both routers in access point mode? (without chaining them, connect both to the modem directly)

If you have to find excuses you probably shouldn’t buy it. Just wait until the 3060 releases. 

If you have to find excuses you probably shouldn’t buy it. Just wait until the 3060 releases. 

If you have to find excuses you probably shouldn’t buy it. Just wait until the 3060 releases. 

If you have to find excuses you probably shouldn’t buy it. Just wait until the 3060 releases. 

If you have to find excuses you probably shouldn’t buy it. Just wait until the 3060 releases. 

After so many results I would consider backing up your important files and reinstalling Windows altogether.

Dual channel could greatly help. I would just get another 16GB stick that matches your current one. Price difference between 2x8GB and 1x16GB shouldn't be particularly high.
 
What's your GPU and CPU usage and temps when playing?

Dual channel could greatly help. I would just get another 16GB stick that matches your current one. Price difference between 2x8GB and 1x16GB shouldn't be particularly high.
 
What's your GPU and CPU usage and temps when playing?

Certain pins could do that, yes. It could also be a bad RAM stick or slot unless you tested them elsewhere.