I was recently setting up Plex in Docker and wanted to use the iGPU for Quick Sync on my 13700k. I passed through /dev/dri, tested transcoding, and noticed that it wasn't using hardware transcoding. Upon further investigation, I saw that /dev/dri/renderD128 wasn't present on the host or in the container.
After performing a fair bit of troubleshooting, I decided to try taking out the IPMI card (ASMB9-iKVM) that came with the motherboard. After doing this and rebooting, /dev/dri/render