So, I'm also coming from the Plex thread and someone posted the ICH77's Jellyfin build
The hardware:
Tiger Lake 1135G7
16gb RAM
OpenMediaVault 5 (Kernel 5.10)
On Ich77's container, transcoding works as expected with no artifacts, with a small note, direct play does not trigger HDR to SDR and video is choppy (But that's maybe the WebUI, no choppiness in Android app), triggering transcoding does trigger HDR to SDR and works flawless. So it's maybe down to linuxserver's build (or Plex eventually) not using the latest drivers ?
Also thanks for the effort, it's a sight of relief to see that it can work