Issues with Transcoding on Proxmox

[TheDreadPirate]

root@jellyfin-tvFestplatte# sudo apt list --installed | grep intel

WARNING: apt does not have a stable CLI interface. Use with caution in scripts.

intel-gpu-tools/jammy,now 1.26-2 amd64 [installed]
intel-media-va-driver-non-free/jammy-updates,now 22.3.1+ds1-1ubuntu0.1 amd64 [installed]
intel-opencl-icd/jammy,now 22.14.22890-1 amd64 [installed]
libdrm-intel1/jammy-updates,now 2.4.113-2~ubuntu0.22.04.1 amd64 [installed,automatic]
root@jellyfin-tvFestplatte#

If I understand how Proxmox works, I think you also need to ensure that these same packages are also installed on the Proxmox host.  You may need to add "non-free" to the apt config on Proxmox since Debian doesn't include it by default.