Are the hardware encoders even good? I thought that unless you need something realtime, it's always better to spend the cpu cycles on a better encode with th software encoder. Or have things changed ?
The file size is also problematic I've had hardware encodes twice as large as the same video encoded with CPU.
Connect credit card, open a web UI, send the command, the files, and eventually get the output?
You just need to use the hetzner API's to put all your video on a shared drive, write a simple job runner in whatever language you like or even simpler you could write your commands in a text file on the shared drive. Write a simple script to mount the shared drive, look for the job file on machine startup; then have your machine delete itself via hetzner API. Email yourself before that. There, you have your weekend project.