Thanks Christian for the feedback. I did try to use spice with GL, but kept getting an error trying to start the VM with it enabled and didn't go down that rabbit hole yet. I had passed through that GPU to my VM and no matter what I tried to do, updating Windows or drivers, trying to delete the other display and video through virt-manager (couldn't seem to delete them all), OpenGL wasn't showing as installed. Maybe if I'd deleted the display and video from the virsh xml file it would have worked, but I decided to start from scratch and got it to work finally so here are the steps I took if anyone else runs into this in the future.
Ubuntu 18.04 with QEMU (I have 3.1.0, would likely be similar with 2.11 or others). There are a few steps needed for Nvidia cards, not sure what would be needed for AMD. This guide is what I mostly mimicked to get everything working including my steps below. This was another one with similar info on Nvidia card setups.
As a note - when I first physically added the GPU, I could no longer access my machine over my network (headless) because adding the GPU changed the network interface which broke my netplan. Could have connected a monitor, but I have an IPMI port on my MB so connected that way and got the new network interface to update netplan.
Create Windows 10 VM in virt-manager - at the end choose advanced options
In Options - use OVMF bios and Q35 chipset. SeaBIOS doesn't work, had to "sudo apt install ovmf". OVMF can't use IDE drives, so changed to SATA to start (SCSI didn't work either), made Virtio later.
In Options - delete all display and video devices
In Options - pass through PCI devices of GPU video (have monitor directly connected to Nvidia video card) AND audio (failed with only video)
In Options - pass through usb keyboard/mouse (since deleted all display and video options to be safe, couldn't interact remotely)
Start VM and load Windows 10 - on first startup it dropped me straight to the UEFI shell which I had to exit out of and took me to the BIOS where I could go to the boot menu and choose the Win10 iso I'd attached as a CD over SATA to boot from.
After Windows loaded and I'd shut the VM down, I edited the XML per the above guides to be sure I didn't have the Code 43 error with the GPU (specifically adding the 3 lines where noted - "vendor_id state='on' value='1234567890ab'/", "hidden state='on'/", and "ioapic driver='kvm'/").
Load Virtio drivers and utility
Load latest Nvidia drivers
Check for OpenGL and it was finally there.
Installed Sketchup and it ran just fine.
I usually use remote desktop for Windows VM's but I still wanted to try to have the ability to connect from virt-manager, so after it was all working, I did go back and add a VNC display and Virtio video to the VM so I can connect and interact through virt-manager or the like. This only seems to work if the Nvidia monitor is physically disconnected, otherwise I get a "guest has not initialize the display (yet)" which I'm sure there is a solution for, but I don't plan on having a monitor connected anyway so I have not investigated that.
Thanks for the input here and my previous post Christian, I'll add a short note to the old one as well linking here as they are related.