Earlier quoted context omitted.
What features is it missing, exactly?
I have always had issues with playing high bitrate BluRay remuxes, with HDR and DTS 5.1+ audio. Granted the last time I tried JellyFin was January 2025 so it is possible this has changed. Have there been improvements on this front?
Transcoding is a whole can of worms I chose to avoid by playing everything directly.