It sounds like you're trying to make a workstation from a server board.
Normal on server boards.
Every server board does this. They'll work with headless GPUs that don't have VGA out like Tesla cards.
Usually iKVM is there to manage the server. GPUs are providing services other than primary...
We're using ConnectX-3 Pro EN cards since they worked out-of-box with Proxmox VE 5.3.
We've got two new nodes, both with the Ethernet only cards, and Proxmox VE 6.0 isn't recognizing them. Is anyone else experiencing this?