I'm using Monterey daily, so which ones? The top bar/toolbar is smaller than any windows bar, dock size is fully customizable, menus are normal size I'd say.
Rest of space is used by applications, not wasted by system. Coincindetally, none of them are really native. Firefox, jetbrains IDEs, Iterm (well, this one is, but might as well not be since it's just a terminal), Spotify, Slack.
No, don't compare modern OSes to each other, they're all infected with the same disease so this comparison is expected to be bogus. Compare the native controls of macOS Monterey to those of Mavericks (10.9), for example. Or Windows 7.
The bottom bar is way larger on Windows than on Monterey. There is nothing like the empty top bar on a Monterey as on the control panel window here. Point to mac here.
If you click on "About this mac" you get the same kind of logo that you get in this Windows photo, so they are about equal there.
There's no obnoxious widgets on Mac, at least by default. I don't remember if they were default on 7 (I think they were on Vista, but that's a different animal). I guess half a point to mac?
Rest of space is used by applications, not wasted by system. Coincindetally, none of them are really native. Firefox, jetbrains IDEs, Iterm (well, this one is, but might as well not be since it's just a terminal), Spotify, Slack.