I haven’t managed to get the GPU properly working when passed through to a Jellyfin docker container, I think you need to recompile ffmpeg or something. If you can get that working I imagine the G610 would be great for it.
Software transcoding though has been great, I don’t need it too often but it’s a lot beefier than the Pi4 so I’ve had no troubles.
I don’t know much about other alternatives, but my understanding is they’ll mostly be between the performance of the Pi and any RK3588 board like the OrangePi. When you’re looking for one, make sure it has an armbian image.
Edit: I managed to get hardware transcoding using docker.io/jjm2473/jellyfin-mpp.
Based on your fans it’s more likely too much air + high initial temperature causing uneven cooling. I assume with those fans you’re trying to print really fast?