From what I have gathered online, it seems like most people believe that macOS is (slightly) more private than Windows. macOSshow you detailed characterization of the telemetry, and you can turn most of it it off; whereas you cannot turn off basic telemetry in Windows.
I cannot verify this claim, since I never owned an apple product.
That being said, if I have to use a closed-source OS, I would probably choice window, since I am more familiar with it and it is (slightly) more open than macOS.
I am probably going to get downvoted to hell for this, but powershell is pretty good.
You can write a whole project in powershell with proper intellisense. I think microsoft also sprinkled some f# type provider magic in it, so the programming experience is rather nice.
imagine writing complex logic in bash, zsh or even fish.
Typically the abstraction to draw elemnts inside a app window is in the application framework, like GTK, Qt, Electron (chromium), etc.
This is also why apps built with the same framework typically have the same problem on wayland (looking at you, electron).
The abstractions you are thinking of is not in the window manager, which only controls things outside of the main app window, like tiling, border, window top bar, etc.