I carry an M1 MacBook Air, and a iPad Air 5th-gen. They both have identical fanless M1 Apple ARM silicon, both have identical ram (8GB) and identical storage (256gb), it's practically the same device. I even also carry the iPad Magic Keyboard. I have to carry two sets of everything, just because Apple artificially prevents any of their own software from working on any of their own hardware.
It makes perfect sense to me that, when in tablet/touchscreen interaction, I get a traditional iPad experience.
It makes zero sense, that when I attach the $300 traditional keyboard/trackpad to that iPad Air, I get thrown into a weird iPad-kinda-pretending-to-be-a-laptop-but-failing mode, where you "kinda" have a mouse cursor, and "kinda" have windows (but only 2 or 3!) and you can "kinda" resize them, and you can "kinda" have an external display (but despite being huge, you still can't have more than 3 windows!).
macOS already works great, "iPad Stage Manager" feels like a bunch of people trying desperately to justify breaking macOS conventions and UI/UX, mostly for no good reason.
There's no reason I couldn't be put into normal macOS, and even have my existing iPad apps still running (the software portion of this already works on macOS today, iPad apps run on macOS right now! You just cant experience this on any of the devices that have touchscreens -- you can't do this on the devices that would most benefit from it.)