On proxmox you should be able to share any GPU (integrated or dedicated) to multiple LXCs while keeping it accessible to the host. I use intel integrated GPU in LXC for plex, jellyfin, and one with just ffmpeg I use to convert videos occasionally. I used these instructions as starting point/base when I set mine up on proxmox v7.x, …proxmox.com/…/plex-hw-transcoding-lxc-and-jasper…
I had looked at instructions to assign the GPU to a specific VM but it looked like way too much work and people were saying it didn’t always work for the 11th gen iGPUs. Thankfully I ran across the sharing method and it’s been running stable since.