shikigva is now only used by whatevergreen for macOS 10.15 and below.
For macOS 11+, it uses unfairgva.
In my recent testing, using unfairgva=1 is the best choice for DRM & H/W encode/decode with SMBIOS ID's other than iMacPro1,1 with Polaris dGPU (and iGPU disabled).
For iMacPro1,1 unfairgva...