My raspberry pi 4 has been running as a home server and gitlab runner under my tv stand for a few months now and works great! I just need to set up a backup scheme at some point since the whole thing runs on an sd card. It seems easier than ever to repurpose old hardware for home servers with docker and all the great projects out there!
OT: In my experience "set up a backup at some point" all too quickly becomes "shit, I _knew_ I needed a backup".