Do you have the Intel drivers installed on your machine? Are GuC and HuC working?

sudo reboot
sudo dmesg | grep i915
sudo cat /sys/kernel/debug/dri/0/gt/uc/guc_info
sudo cat /sys/kernel/debug/dri/0/gt/uc/huc_info

On Debian I had to manually download the i915 full driver Zip, extract it, take out the Intel drivers, and put it in /usr/lib/firmware

Then hardware acceleration worked on my Arc380.

If you use QSV, your CPU iGPU will be the one that can use it, so make sure to set your render device in docker to the iGPU and not the RTX 2060