We want to see 3D in SPICE (not local), we can use pci passthrough. Is it possbile in PVE 5.1?do you want 3D acceleration in spice (for remote), or do you want pci passthrough your vga card (for local) ?
for spice, it's not yet available in proxmox. we need to add support for virtio-gpu and other 3d stuff. (and I think that only recent linux guest support it, not yet windows guests)