How do I need to configure jellyfin in order to work properly?

I added

device:
  - /dev/dri

And I tried /dev/dri/renderD128 but both don’t work. Moreover, I enabled encoding in HEVC format, hardware encoding and selected hardware accelleration with intel quicksync (QSV) and enabled hardware decoding for H264, HEVC, …

But if that’s enabled, transcoding doesn’t work at all on the player.