Those that are implemented have been very reliable in my experience, I think that labeling them “alpha-quality by Linux standards” is a ridiculous claim
Those are all perfectly acceptable limitations for a POC. And the GPU drivers are particularly well-made. But it doesn't really come close to how seriously AMD and Intel take Linux.
even in the m1 there are 4 WIP in the support table, 2 TBA and 10 non mainline boxes for the M1 pro