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.
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.