You could potentially run a backup site or a different lemmy instance, but that requires people possibly knowing your real IP and port forwarding (unless you use a VPN or port tunnel), technical knowhow, and constant uptime. If you don’t mind ruining the PC, you could also test software / cracks on there. (Turn off your internet if you’re planning on doing this.)

Honestly, the best way you can help is contributing to the wiki and helping people out in Divolt and on here. No extra computer needed.

I don’t think you can help the site directly but you cloud use your PC to seed torrents. That seems like the simplest way to help the fmhy community. Seed stuff that you like and focus on the less popular stuff with not many seeders