(You do use a window manager, btw, it's the thing that puts the title bars on your windows and lets you move them around. On macOS it's integrated in, but on Linux you have to choose one. There are many, all of which have some failing. Except for sawfish, whose failing is that it is no longer maintained.)
Open 3 terminal windows. Try to switch back & forth between just two of them with a keyboard shortcut (without mentally tracking whether or not to press Shift). You can't.
Open a browser and two terminal windows. Try to switch between one terminal (your editor) and the browser window (your reference docs), without also bringing the other terminal above the browser window, covering up your docs. You can't.
> Is this going to be some Kind of major epiphany?!
If you don't use several windows per app, probably not. But, I do, and macOS's window manager is awful for it.
cmd+` gets me there, no problem at all
> Open a browser and two terminal windows. Try to switch terminal and the browser window, without also bringing the other terminal above the browser window
you got a point there. alt+tab is gonna surface both terminal windows above the browser.
No, this cycles between all 3 of them. As I said, I want to swap back & forth between just two of them. Extrapolate this behavior from 3 windows to 15 and you start to see the problem.