@karmanyaahm - The motherboard headers also carry 2 ports worth of data pins - ever wondered why you insert a single plug into the motherboard yet your case has 2 ports on the other end? Note: I don't believe this is the case with the newer USB 3.1 Gen 2 (Type-E) motherboard header.
Dual core is fine for all those tasks, but MacBook Air money for a device to do those tasks is pretty insane. You could get a chromebook that does all those tasks just as well for a fraction of the cost.
Do you have any family you can ship a NAS to? A Synology NAS would be perfect for this, just configure remote access to it before you ship it (Synology QuickConnect) and then you can setup one of the many applications to backup to. If you want to get more advanced you can get another Synology NAS for your house to encrypt the backup before sending it so the data on the other NAS is protected in case that gets stolen. Additionally you can automatically backup directly to a number of cloud services from the NAS if you want a true cloud backup. Also the 1 bay units use less than 15W of power and are super quiet so the person won't notice it running 24x7.
Software Raid is a dirty word. Almost a swear word. However, File Systems like ZFS and UnRaid have resolved almost all of the issues and for most of us are better than the dedicated Raid cards for non-enterprise work, aka prosumer stuff. ZFS is extremely resilient, and very fault tolerant. However, ZFS is designed to use the all of the system's resources to support a server role. I've looked at Un-Raid, and played with it small scale and I like its easier implementation of VM features and SSD accelerators. Though its not enough to get me to jump from FreeNAS which has been 100% rock solid once I got past the initial learning/teething issues.
Windows software raid, aka Storage Spaces, is, terrible by comparison. Hardware based Raid is better. Storage Spaces has got some problems and I wouldn't trust my data to it at all. Even if all I was doing was a mirrored configuration. I'd rather run two drives separately with a Robocopy scheduled task to sync the drives.
Raid 5 in the traditional sense has some issues. ZFS and UnRaid have fixed these issues. Hardware Raid 5 has a problem in that lets say you have a 5 drive array. If a drive fails when you replace it you need to rebuild the 5th drive. This puts major stress on the remaining 4 drives as they need to reconstruct the 5th drive's data. If you are working with smaller drives, its not big. But as you get into the 4,6,8, and god forbid 10TB drives the stress on the remaining drives means its going to take a LONG time to rebuild that data. Thats a lot of heat buildup and thrashing, so the chance of a 2nd drive failure increases.
During the rebuild process if a 2nd drive fails that's it, kaput, your data is GONE. ZFS, the underlying file system of FreeNAS can't save you from this either, but it is not a total loss. You can recover some of the data, just not all. So as you get into the larger sized disks its better to build with Raid-6. I built a 40TB RaidZ1 volume, and as sometimes happen I had a single drive fail out under MFG warranty. While I was replacing the drive I had no redundancy and it was an uncomfortable feeling. Since I didn't want to wait two weeks for a RMA, I bought a new drive locally. After I replaced it and it rebuilt, I backed up all of the data, wiped, and rebuilt the array as RaidZ2. I feel MUCH better now if I have a failure knowing I can still lose ONE more drive.
If you are dealing with smaller 2TB-3TB drives, the Raid-5 vs Raid-6 argument affects you less.
If you are going to run a Plex VM I suggest upping the processor to something with more oomph. I ran a FreeNAS / Plex VM based on a AMD A10-7850k. The CPU was about 25% slower than the 2200g you listed.. It was capable of about 3 1080p Transcodes at once, but where it struggled hard core was the nightly analyze task where Plex analyzes your media for Chapter and Seek thumbnails. It was also sluggish to respond when spooling up a 2nd or 3rd transcode. It just didn't have the ability to handle multiple threads well.
When I added TV Seasons it would chug for hours and hours to process it all. God help it if I ripped an entire box set containing multiple seasons. It chugged for days.
I think you'll be initially happy with the 2200g, but later find it doesn't give you the HP you will eventually be looking for. I can see you out-growing it quickly. In the end going with a better processor will save you money as the system will have a longer shelf life as your media collection grows and your demands increase.
I bought the the 4790k when I upgraded from the 7850k build for FreeNAS and it has been rock solid and super responsive. Its been 5 years and it's only now reaching the end of its life because it can't handle 2 4K HDR transcodes at once. The next system I build will be capable of handling 4-5 4K HDR transcodes simultaneously. Which means for standard 1080p content it will basically sit at idle doing nothing. For a mid-range CPU I really like the Ryzen 5 2600, I built one for my nephew and its would have made an excellent budget CPU for a Media Server.