I don't see how you can come to this conclusion. The first generation of AMD mobile chips on a comparable process node to Apple only just released and the 7840u

I don't see how you can come to this conclusion. The first generation of AMD mobile chips on a comparable process node to Apple only just released and the 7840u is even with the M2 Max in multi-core performance while using less power. I think the conclusion to draw here is that Apple's efficiency advantage seems to be rooted outside the ISA. Their idle power usage from what I've seen is very impressive.