I have 2 RTX 2070S that are assigned to separate Windows VMs. The pass through of the video, audio, and USB controller work with one small exception. After restarting the host I cannot boot either VM without unplugging the usb hubs from the graphics cards. After both VMs are started and running I can plug in the hubs and all devices (mice/keyboards/printers/dac/Bluetooth adapters) work fine. After the VMs are started I can shut them down and restart them without issue as long as the host has not been power cycled. It is also worth noting that I have to unplug both usb hubs for either of the VMs to start (maybe a side effect of using identical cards?).
The pass through works nearly flawlessly after the VMs are started initially without USB devices connected. I have passed the devices through using SpaceInvaderOne's tutorials and followed the instructions on the Unraid FAQ on RTX pass through. I am passing through the VBios, but tested without and received the same results. I have tested using both Q35 and i440. It also doesn't make any difference if the devices are configured as multifunction with 4 devices in the same slot or 4 devices each with their own slot in the VM config.
EDIT: added diagnostics data.