USB cards are really hit or miss for VFIO. I've got a vive set up and working on a https://www.amazon.com/High-Point-PCI-Express-RocketU-1144D/dp/B015CQ8DCS

But it's obviously not the cheapest card (it does have 4 independent IOMMU groups though).

My recommendation is to go to a used hardware shop and pick up a few used, cheap USB2 cards (pretty sure the Vive was 2.0) and then try and see what luck you have. The card I use for USB audio passthrough I found this way for like $4 (actually on my first try).

EDIT: should also point out mine does not have a SATA power or other extra power source other than the PCIe slot, so it's probably not a power thing.