Server Build Components selection help

Hi all.
I am planning to build a server running proxmox as the host OS. I will be running firewall + truenas + windows vm + containers.
I would need to passthrough certain devices to these vms, a gpu with vifo for windows + media server for transcoding, a nic for the firewall and two hard drives passthrough to truenas. I also will be using two nvme drives for the proxmox data and vm data (in raid dont think i need passthrough for this?)
I am quite stuck on finding a motherboard that will allow me to do this, im looking at an am4 motherboard to pair with a ryzen 9 5950x. Currently most motherboards have only one pcie and nvme slot wired to the cpu with the rest being wired to the chipset which will cause problems of iommu groupings. I would need a minimum of two pcie slots (NIC and gpu) connected to the cpu, the two sata drive sconnected to cpu (not sure if this is posisble?) and possibly two nvme to cpu unless i dont need to do passthrough to proxmox for vm and os storage which i do not think i need to.

Currently ive found:
Asrock x570 steel legend

This motherboard claim to have two x16 slots to the CPU ? (unless ive read this wrong), and same with the nvmes.

The tiachi x570 also has two x16 slots to the CPU however the boards a bit pricy.

Am i looking at this problem wrong ? Is there work arounds ? ( I know u can acs and iommu group settings on bios to split them but thats a security/stability issue ive heard), or are there reasonably priced motherboards out there that will let me get this job done?
Thank you.

Well, the lanes are connected to the CPU, but if both slots are filled each will only connect with up to 8 lanes.

Remember, the CPU in an AM4 socket only supports 24 PCIe lanes in total (+4 lanes connected to the chipset)

That is good to know i am more concerned about passthrough. I think 3.0 x8 is enough for a mid/low range gpu and x8 is more than enough for a NIC. NVME drives I dont believe needs to be passthrough as its being used by the host proxmox.

That settles it then. X570 Steel Legend + 5900XT /5900X.