AFAIK the only way to achieve this is to pass-through a GPU via VT-d. This config does not appear to support this though. If you search github for this line, you will find other configs that support doing this- https://github.com/kholia/OSX-KVM/blob/master/macOS-libvirt....
Edit: It's relatively easy- blacklist (or uninstall) GPU drivers from host machine, and pass the PCI address to qemu. Performance is not perceptibly different from native. Other things you probably want to do are enable hugepages, pin virtual cpus to physical cores, and use vfio for network- https://github.com/pmj/virtio-net-osx.
It's also possible to run boot OSX using UEFI mode, which removes the need for the binary blobs in this repo.
Hardware acceleration can be done using PCI passthrough to pass your graphics card on to the guest OS. IOMMU and VFIO are two terms I commonly see associated with this, but having never done it myself I am not sure what the difference between them is - perhaps someone can chime in?
VT-d = Virtualization Technology for Directed I/O
which basically means the CPU has an IOMMU, the IOMMU is a piece of hardware for doing PCIe DMA re-mapping to provide VM isolation. VFIO is the linux driver for passing through IOMMU devices.
The script seems to use qemu's default VGA graphics chip. I'm not sure whether you can get anything faster to work, given Apple's limited graphics driver support.
Edit: It's relatively easy- blacklist (or uninstall) GPU drivers from host machine, and pass the PCI address to qemu. Performance is not perceptibly different from native. Other things you probably want to do are enable hugepages, pin virtual cpus to physical cores, and use vfio for network- https://github.com/pmj/virtio-net-osx.
It's also possible to run boot OSX using UEFI mode, which removes the need for the binary blobs in this repo.