[rifty]

Personally, I think the trade offs for more window space is worth it versus window positioned app menu bars. If you really are trying to maximally optimize menu bar navigation you go with the menu bar as a context menu wherever your cursor is, or a key command to prompt searching for the menu option you want to use.

As for 3, the way you'd solve this while retaining the 'global' menubar style is by treating screens more individual and having a screen unique menubar. Introduce screen focus, and have the screen focus follow where the cursor is. Further you could make it so that when a screen regains cursor focus it also refocuses the last window on that screen. The menu bar would then serve the purpose of visually indicating and emphasizing which app on which screen has latent focus even when the screen lacks focus itself. (Which now saying it honestly might have been an original MacOS consideration before losing focus caused window dimming)