R7 260X No GPU Acceleration

I can’t seem to get my Sapphire R7 260X working in Big Sur / Catalina, despite it being in the supported GPU list. Everything else works perfectly - just no graphics acceleration. I have tried to spoof the device ID using SSDT-GPU-SPOOF to a 7770, 7790, R7 370 and a few others. No success with any. I suspect my GPU spoof isn’t applying properly because, in system report, my GPU is always reported as ID 6658 (the actual ID) and not any of the IDs I spoofed. Is this intended behaviour? I thought the ID was meant to change to what I set in SSDT-GPU-SPOOF? How can I check if the spoof actually applied? Also any other ideas to get this thing working would be appreciated.