- Platforms
Very basic OT, as I'm getting into all this myself.
What is a Home Server/NAS?
A computer or machine primarily aimed at serving other computers/devices. These come into two main types Pre-Built or DIY, the latter being very similar to building your own PC.
What can I do with my own Server?
Hundreds of things, but the most common uses are for Home Media Storage, CCTV, Access to share drives for multiple users, long term secure file storage, Virtual Machines, self hosted email etc etc.
What are the advantages/Disadvantages of a pre built system?
Guaranteed compatibility and bespoke software, that "just works", small discrete size and very low power (perfect for 24/7 availability). Synology, Asustor and Qnap are the main players. The downsides much like PC building are that you can't upgrade/modify easily, you may be tied into certain software and you won't get as much performance for your money (a lot of that money is invested in the software that device uses).
What are the advantages/disadvantages of a DIY system?
Greater expandability, more performance for your money, can match your exact needs, easier to swap out parts and upgrade. Downsides are that you must purchase your own software, when problems occur (and they will) it's up to you to solve, takes time to research.
My Setup
There's so much to cover beyond this, it would be pages long, so its probably easier to just go into detail as the need arises. My setup is a DIY solution, its primarily a media server. I use a Fractal Define 7XL that can hold 20+ Hard drives, so well over 300tb+ (It's 120tb at the moment). In this case it is so large because I want to host a large amount of content in the best quality possible. Depending on your needs an all SSD NAS is perfectly viable. I do have a 4tb NVME Cache drive, to keep all my apps on, so the server runs really fast for everyone (and new files are transferred to the main array over night). I use Unraid as the OS as if a drive fails it can be recovered with no data loss and you can use mixed disk sizes. Just note the Parity drive in your system should always be the biggest drive.
I then use Jellyfin as my media server, accessed by about 8 people (close friends and family). It takes more work to setup then say Plex, but it never "phones home" and local users can use the server even when the Internet goes down, plus all the feautes Plex has without the Paywall. I have Sonarr setup to download my episodes via Usenet so very little manual work is required by me now, as all my quality preferences have being set. Next up I'm going to look into Radarr to automate my movie solution and get an app on my phone to control it all, when out and about. Other uses for my server so far have been putting family pictures on as a secure backup, and storing my classic game ROMS.
What is a Home Server/NAS?
A computer or machine primarily aimed at serving other computers/devices. These come into two main types Pre-Built or DIY, the latter being very similar to building your own PC.
What can I do with my own Server?
Hundreds of things, but the most common uses are for Home Media Storage, CCTV, Access to share drives for multiple users, long term secure file storage, Virtual Machines, self hosted email etc etc.

What are the advantages/Disadvantages of a pre built system?
Guaranteed compatibility and bespoke software, that "just works", small discrete size and very low power (perfect for 24/7 availability). Synology, Asustor and Qnap are the main players. The downsides much like PC building are that you can't upgrade/modify easily, you may be tied into certain software and you won't get as much performance for your money (a lot of that money is invested in the software that device uses).

What are the advantages/disadvantages of a DIY system?
Greater expandability, more performance for your money, can match your exact needs, easier to swap out parts and upgrade. Downsides are that you must purchase your own software, when problems occur (and they will) it's up to you to solve, takes time to research.
My Setup
There's so much to cover beyond this, it would be pages long, so its probably easier to just go into detail as the need arises. My setup is a DIY solution, its primarily a media server. I use a Fractal Define 7XL that can hold 20+ Hard drives, so well over 300tb+ (It's 120tb at the moment). In this case it is so large because I want to host a large amount of content in the best quality possible. Depending on your needs an all SSD NAS is perfectly viable. I do have a 4tb NVME Cache drive, to keep all my apps on, so the server runs really fast for everyone (and new files are transferred to the main array over night). I use Unraid as the OS as if a drive fails it can be recovered with no data loss and you can use mixed disk sizes. Just note the Parity drive in your system should always be the biggest drive.
I then use Jellyfin as my media server, accessed by about 8 people (close friends and family). It takes more work to setup then say Plex, but it never "phones home" and local users can use the server even when the Internet goes down, plus all the feautes Plex has without the Paywall. I have Sonarr setup to download my episodes via Usenet so very little manual work is required by me now, as all my quality preferences have being set. Next up I'm going to look into Radarr to automate my movie solution and get an app on my phone to control it all, when out and about. Other uses for my server so far have been putting family pictures on as a secure backup, and storing my classic game ROMS.