Take a look, and consider one more option (I have this setup in one of my workstations).
A second GPU. Older is fine, I have an older quadro 2000 in one machine thats great for cad, when I load up my VM for AutoCAD architecture, thats the GPU its using.
I have a few others with quadro 620s in them, the Intel iGPU is accessed shared by being an lxc, the quadros I pass through to the VMs. Some need very different configs, so I only power up the VM when I need it, so they can all use the same passed through GPU.