I don't really care how slow handbrake is on Linux because I first use makemkv to rip the blurays to disk, and then run HandBrakeCLI in a bash for loop against the *mkv files.
The hardest part is putting the blurays in the machine, but the bash for loop is easy you just come back a week later and get the *mp4 files.
Your reverse proxy, as well as the upstream services, can all live inside your wireguard vpn. Of course this eliminates the need for having a registered domain or ssl encryption or publicly exposing the reverse proxy.