Unable to get intel arc working in Debian 12 VM, device recognized, no /dev/dri entry

[Fate]

I don't use Truenas. So your passthrough might not working right. Maybe your question should be redirecting at the truenas forum.

But according to the arch wiki
https://wiki.archlinux.org/title/intel_graphics
your gpu should be using guc=3

Any output on journalctl or dmesg?

I needed these packaged for VA-API on arch so your packet names may vary:
pacman -Sy libva-utils
pacman -Sy intel-media-driver
pacman -Sy intel-gpu-tools

In addition I needed those for Quicksync:
pacman -Sy intel-media-sdk
pacman -Sy onevpl-intel-gpu

You can check guc status via:
cat /sys/kernel/debug/dri/0/i915_gpu_info

Also i would recommend to add "non-free-firmware" to apt/sources
and get the "intel-microcode" package. (maybe optional)