You’re right that lots of Windows apps were designed with Keyboard only workflows in mind. It’s a shame that MacOS has so many points where if you don’t have a mouse you’re out of luck.
There is one major improvement you can do on Mac, at least for menus:
Like the linked article says, every time I set up a new Mac, I’m annoyed that this isn’t the default.
Obviously depends on your workflow but I think I use mouse only on websites on macos (with aerospace)