The only way I've been able to get good virtualized 2D performance without providing a GPU directly to the VM has been to use a display manager where you can disable compositing. Otherwise, you end up having to use a software 3D rasterizer like LLVMpipe, which can be quite slow.

The native display managers for XFCE, MATE, and (I believe) KDE allow you to disable compositing. GNOME and Unity's native display managers don't (AFAIK). I have no idea if display compositing can be disabled on macOS.