Since you mentioned high cpu temps, do you have a water cooler? It’s possible that the pump is running at a reduced speed or not at all. If it was functioning fine on windows that leads me to believe that it’s not hardware related like some are suggesting.
I’m not expert but for the sake of getting some discussion going:
Don’t open ports on your router to expose services to the open internet.
Use a vpn when torrenting and make sure your torrent client is set to only use the vpn’s network adapter. This way, if your vpn drops out the torrent client can’t reach the internet.
I keep everything local and use Tailscale to access things while I’m away from home.