Windows and Linux actually feel pretty close these days, and I don’t generally feel any friction switching between them. But when I try to use a Mac it’s another story entirely. That OS just makes no sense to me - the keyboard shortcuts all seem to be insanely bad choices, just inconsistent with huge gaps and divergences from the other OSs. It feels so stuck in the 90s

This checks out. My leading mental model to explain this mismatch is that the critique has been from people who are expecting Mac idioms, which I can't speak to. Window and Linux GUI look/feel are fragmented as-is.