Every system has its issues. It's really a question of which issues you can live with and which system ultimately fits your workflow best.
After I got used to working in windows instead of full screen all the time, I can't really go back. Even on Windows I find myself working the way I do on macOS. Full screening every app made more sense on a 1024x768 screen (or smaller). Once I moved to a widescreen display (which happened to coincide with getting my first mac) running full screen felt like the wrong move most of time.
Web pages would look something like this:
| <- whitespace -> | <- content -> | <- whitespace -> |
| | Lorem ipsum | |
| | dolor sit amet, | |
| | consectetur | |
| | adipiscing | |
| | elit. Morbi | |
| | convallis ante | |
Making the window smaller meant less wasted space and less blinding white space. Once I got used to that idea, it carried over to most other apps.It is situational but I think on a modern wide screen(or screens) if it is a single text-like document(like a web page or a terminal) you want 2 or perhaps 3 side by side. if the app implements it's own window management(like blender) a single full screen is best. Overlapping windows are important to have, but almost never desirable, it usually happens because you ran out of room.
The problem I have with this is that I was using a 1600x1200 21" display in 2000, and got used to workflows for it back then.
I am currently running a 16" display at a similar fractional scaled resolution (because Apple stopped understanding DPI after shipping the first LaserWriter, apparently).
Over that time, my eyes have not gotten better to match display DPI, so I'd rather have web sites just adjust the font size so that there are a reasonable number of words per line instead of rendering whitespace.
Non-full-screen windows would make more sense if Apple supported tiling properly, like most Linux WMs and also modern Windows.
MacOS sort of supports tiling in a "program manager shipped it + got promoted" sort of way, but you have to hover over the window manager buttons, which is slower than just manually arranging stuff. If there are any keyboard shortcuts to invoke tiling, or a way to change the WM buttons to not suck, I have not found them.
This is just that things are (poorly) designed now as mobile-only and not even mobile-first.
> After I got used to working in windows instead of full screen all the time, I can't really go back.
Sorry if this comes across as disrespectful, but it smells like Stockholm Syndrome. You are choosing not to use the full extent of your screen estate, and that is your fine choice, but that is no excuse for making it hard. If you compound the whitespace, the thick borders and the generally oversized UI controls, not much of "productive space" remains available to get the work done. I am not interested in macOS as a content-consumption-first vehicle, though that's clearly where Apple is steering.