Seeking Motheboard with good IOMMU for Proxmox given a limited selection

Hello! I am planning on building a machine to run Proxmox. Within it, I plan on running TrueNAS for storage, Nextcloud and a few other virtual machines for game servers, homelab services (website, ssh, vpn, remote desktop, pihole and more!) and for general VMs. Sadly, I am a newbie at Proxmox and the requirements that I wish to fulfill my wishes. The requirements that I am seeking are quite simple: ECC memory support and PCI passthrough. Given budget constraints, I have narrowed down the search to a AM4 motherboard together with a 5500/5600/5600X (whichever I find available at the time) and a cheap gpu to allow Proxmox to post and run.

With those requirements, the only motherboards that seem to fit all of them in order of ease-of-aquisition (some would need to be imported, others are available where I live for big markups) are the Asrock x570 pro4 (not the mATX version), the x570 Aorus Elite and the ASUS TUF x570 plus.

Sadly, even scouring the internet, I haven’t managed to find the IOMMU groups of the x570 pro4 (only the mATX seems to be talked about). Could I be reasonably certain that it has at least all the PCIs are in separate groupings? If yes, that would be a life saver! (mainly I would need to pass-through a PCI sata controller or the SATA of the harddisks themselves to TrueNAS) (If not, I will attempt to get the x570 Aorus Elite).

If any of you have/had a x570 pro4, please fill me in on what you have learnt with it!
ps: would a cheap gpu be enough to run Proxmox and a few VMs? I would guess that yes, but reassurance would be great!

Thanks for your time reading this and any future advice!