Just to update on this and close the topic. I’ve talked to Nvidia and was informed that vGPU approach is required whether it’s a pass-through mode or splitting GPU to multiple users. vGPU requires a valid license and installation of video driver on the host and on the guest. To my best knowledge there is no way to directly pass through a professional GPU without using vGPU.
Before I’ve figured out the solution with vGPU I’ve tried all kinds of Proxmox tricks like setting kernel boot parameters, changing GPU PCIe physical slot, etc. GPU was visible in the guest OS but the driver would not work with it. On the same guest VM I can pass RTX 3090 without issues.
RTX 6000 Ada works fine with the same linux driver on bare metal.
Kudos,
Alex