That appears to focus more on Linux machines performing GPU passthrough to virtual machines, rather than Proxmox-specific setups. For Proxmox, the primary requirement is the vendor-reset module available at https://github.com/lok0919/vendor-reset/tree/navi-32. However, the original DKMS install and uninstall scripts had limitations, so I improved them and submitted pull requests to both repositories mentioned.
So start with using my git:
Bash:
git clone https://github.com/jaminmc/vendor-reset
cd vendor-reset
./dkms-uninstall.sh
./dkms-install.sh
cp udev/99-vendor-reset.rules /etc/udev/rules.d/99-vendor-reset.rules
udevadm control --reload-rules && udevadm trigger
This will get the Vender-reset working for your card.