Funny you mention that because on their github they just pushed an update to say that it didn't work M3 and M4.

Sorry about that but this is what is being there in github : Apple M3 or later required. MetalRT uses Metal 3.1 GPU features available on M3, M3 Pro, M3 Max, M4, and later chips. M1/M2 support is coming soon. On M1/M2, RCLI automatically falls back to the open-source llama.cpp engine.