The M1 was beefed up in quite a number of ways. More cores, much bigger GPU, double the memory bandwidth, more clocks, more power, a massive io subsystem that just didn't exist period with thunderbolt, pcie, etc.
You are correct that the architecture was indeed the same, but it was quite a different chip. "Literally a phone chip to begin with, based on", to me, misleads from how different the m1 was. But yes, they appear to share the same architecture.
