@tjkreidl
hmm...generally, the 15 VMs would take up much more resources than just one Host would be able to disperse. Let me explain...
Currently, with VMW, I have just 5 VMs per ESXi Host, and have 3 physical Hosts, 2 NVIDIA Tesla T4 (a bit legacy now) cards in each Host. I virtually passthrough the underlying cards in each Host to each of the 5 VMs. Not entirely sure how VMW does it architecturally, but VMW disperses the load between the cards amongst the 5 VMs. And maybe that's done in conjunction with the NVIDIA driver installed on ESXi. ️Also, the reason I only have 5 VMs per Hosts is because I use them for students to RDP into to run high graphics-need engineering applications (AutoCAD, Revit, inventor Pro). I use Microsoft RDS (really an underrated VDI solution imo) and it "round-robins" the student RDP connections amongh the 15 VMs. I can have up to around 10 RDP connections to each VM. But, according to specs, theoretically I can have around 20 RDP connections. So, as you can see...resources can get tight really quick..thus, only 5 VMs per Host. Anyway, that's what I'm wanting to achieve with XCP. I have a little time...till next summer...to make a decision on what h/v to migrate our VMW VMs off of. My hope is that XCP will be the choice. Ultimately, I'm the one to make the choice, but this would be a definite negative. PVE is my only other option. Not sure they have vGPU passthrough tho either (I have yet to research it).
Thanks for all the info and assist!