I recently transitioned my PC to a SFF case and have the remainder of the computer ready available as a great basis for a fairly modern gaming computer. It will have no problem playing most recent games at 4k/high settings at 60FPS.
Bring your own AM4 CPU and memory, and I’ll help install and run cables at no extra cost. Also, I have a bunch of extra Noctua fans if you'd prefer those for some extra costs.