I usually follow the craft computing video whenever I have to set it up. He has a document in the description with all the things you might need to passthrough a GPU but only like half are needed to passthrough an HBA

www.youtube.com/watch?v=_hOBAGKLQkI

Proxmox wiki has a more concise guide IMO

pve.proxmox.com/wiki/PCI_Passthrough