Advice on building a budget low power Plex + NAS Server (First Build)?

Hi Everyone,

I’ve been toying with the idea of building a low power, budget server for fun. I’m looking at using it to centralize my backups and also as a media server (plex or something). I have some 4K videos that I’d like to be able to play on local streams (Fire HD 4K) and some of my other computers, my other videos are mostly 1080p.

On the storage size I currently have 2x 8TB WD My Books that I’m planning to shuck. Thinking about setting up an UnRAID array. I also have a Seagate Desktop 8TB that I can add to the pool (is this a good idea?).

I want to try to do this for as cheap as possible (ideally less than 200£), and have it not be a power drain (looking at CPUs with 35W TDP). Looking on ebay, it seems like the Celeron 5900Ts are cheaper right now than the LGA 1151 slot processors. I have some spare parts that I can use, a Corsair 600W 80+ PSU, and a case, so I think I’ll need a CPU, mobo, and RAM to get started.

Is this reasonable, or just unrealistic with my budget and what I’m trying to do. I’d love to get any advice and feedback, it’s been a while since I’ve built a computer, and haven’t really done anything on the software side of setting up a server (aside from wsl2 and linux for work), but want to do this as a fun project.