It accomplishes the same thing as Proxmox (VMs and LXC containers, which are “lite VMs” for if you wanted a Linux VM), I recently learnt about it too! It is new, but it was backed by Canonical up until the LXD/Incus split so it’s very solid. Split because Canonical tried to control LXD heavily, so they forked and renamed it Incus.
I just used Incus and it’s very nice, use the profiles to create a profile for “GPU pass through” and “macvlan”, among others you’ll find you want. Then make instances as needed! It was easier for me to use than Proxmox.
Old AMD cards can be flashed with any BIOS that says anything. Maybe the card was used for a scam and flashed to say it’s an RTX 2070, it should have a switch to go to its 2nd BIOS near the top left (when slotted in). And if it doesn’t, you can just get its original BIOS off of Techpowerup’s database and flash it with atiflash, also from Techpowerup.
Picture stolen from some Reddit help thread for a red dragon RX 580.
This is assuming that Linux is reading what the card claims it is correctly. Which seems likely, since reading device IDs is a really important feature that probably works nearly perfectly.