It seems that the mdev-post.service does not start correctly, and mdevctl types returns nothing.
Thats atleast for me on both Ubuntu 22.04 and Fedora 36(with Linux kernel 5.15).
On Ubuntu the "mdevctl types" returns nothing until i restart the service, and on fedora i have to run "mdev-cli -c /etc/gvm/mdev-gpu/generate-vgpu-types.yaml"
I had to spend a couple of hours trying to figure it out, since my vm wasnt passed through any vgpu