jellyfin:
    container_name: jellyfin
    image: linuxserver/jellyfin:amd64-version-12.1ubu2604
    expose:
      - 8096
    networks:
      - media
    volumes:
      - ${DIR_LOCALTIME}:/etc/localtime:ro
      - ${DIR_container}/jellyfin/config:/config
      - ${DIR_media}/data:/media/data
    devices:
      # IntelQuickSync für TigerLake GT2 [Iris Xe Graphics]
      - /dev/dri/renderD128:/dev/dri/renderD128
      - /dev/dri/card0:/dev/dri/card0
    environment:
      PUID: 1200
      PGID: 1300
      #UMASK: 022
      TZ: ${TZ}
      DOCKER_MODS: linuxserver/mods:jellyfin-opencl-intel
      JELLYFIN_PublishedServerUrl: "https://jellyfin/.${DOMAIN_EXTERNAL}"
    deploy:
      resources:
        limits:
          memory: 10G
    group_add:
      - '44'
      - '992'
    labels:
      # Traefik:
      traefik.enable: true # Enable Traefik reverse proxy for the Traefik dashboard.
      traefik.http.services.jellyfin.loadbalancer.server.port: 8096
      traefik.http.routers.jellyfin-public.entrypoints: 'https'
      traefik.http.routers.jellyfin-public.rule: 'Host(`jellyfin.${DOMAIN_EXTERNAL}`)'
      # Secondary domain
      traefik.http.routers.jellyfin-public2.entrypoints: 'https'
      traefik.http.routers.jellyfin-public2.rule: 'Host(`jellyfin.${DOMAIN_EXTERNAL2}`)'
    restart: unless-stopped

Afaik the card0 is only used for rendering to a desktop/monitor and for this purpose you should actually use the renderD128 path.
But not sure either about this stuff. Sort of works for me. At least intel_gpu_top shows activity when transcoding :p