

It was really simple to do in Proxmox.
You will find no name brand HBAs in IT mode on eBay for half the price of Intel, Supermicro, Dell, Etc branded ones. Do not buy the no names. I spent a week flashing and reflashing some cheap one, cycling through cables, etc. Nothing.
My supermicro branded one worked absolutely no issue. And I think it was like $40
It probably took a total of 30 minutes to pass it through and build the VM and everything. It took a couple days to rebuild my data from my previous truenas server but I had 10 TB of data on 4 drives.
The only issues I’ve had have been my own reading comprehension in setting up truenas accounts.
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
https://www.youtube.com/watch?v=_hOBAGKLQkI
Proxmox wiki has a more concise guide IMO
https://pve.proxmox.com/wiki/PCI_Passthrough