I'm using my old Thinkpad T510 as a home server. It's been running for 7+ years already. I only need to dust the vents once in a while.

It has PiHole, Nextcloud, my humble little Netflix clone, and a few other things. If you use ffmpeg a lot, you ought to have more power than the RPi offers. I often SSH into it to use it as a SOCKS proxy in other countries.