I've been watching DustUps ranch on YouTube. Some guy bought wasteland in Texas and is doing this and other stuff to create a forest.
Definitely not an instructional channel because there is a lot that goes wrong so far but he learns as he goes and seems to have a good plan now.
I had an Intel s2600 with dual Xeon and 120 gigs of RAM. It seems like such a good idea to run that as a home server. However, the amount of power that it used because it was older was way too much.
I ended up hunting on eBay and found an old Asus motherboard, Intel chip, ram, and a pny Nvidia card.
I bought refurb hard drives from serverpartdeals and a new case from Amazon.
I recommend starting with a chassis you want and working backwards to help narrow your scope.
I know you wanted smaller but heres what I bought. SilverStone Technology CS382... https://www.amazon.com/dp/B0CKTYSZV9?ref=ppx_pop_mob_ap_share
Also, I run truenas scale with a bunch of apps. Ssd z1 for os. Ssd z1 for transcode and caches. And then 4 drive set for main storage and another 4 drive set for backup of the first set.