> There is no other way to say this: window management is painful on macOS.
Out-of-the-box yes.
> If you open two of the same window (e.g., two Chrome windows), they appear as one in the dock. However, when you press Command (⌘)+Tab, this will only show one entry for Chrome, even though you have two windows of Chrome open.
For app switching I've set the "Move focus to next window" keyboard shortcut to Option+Tab (don't remember what the default is). This works like Cmd+Tab, except it cycles between windows of the active application (i.e. Chrome windows in the above example). It's really quick and smooth since you just move your thumb between Cmd and Option.
There is a slight difference between using Cmd+Tab though - you don't get a preview of the window you're about to switch to, so it's sometimes a bit clumsy if you have many windows open. To solve this I have three-finger swipe down set to display all windows of the focused app (called App Exposé). Don't remember whether this is default behavior. But with this you actually see all windows, which makes it even better than Cmd+Tab in this regard (which only shows icons).
The above two in combination work very well for me and window management is a breeze.
For window snapping I use BetterTouchTool[0] (paid app), but agree that if you need to get corporate IT's blessing to install apps then it's a hassle. Another app I couldn't live without: Alfred[1]. Just its clipboard history management and snippets make it awesome, but it can do so much more, like Workflows which I use a lot for various things). And iTerm2[2] is great.
So in conclusion I agree with OP - if I was forced to use a vanilla installation then I'd prefer most Linux DE's, but being able to install a couple of apps I simply love MacOS and would have a really tough time transitioning back to Linux (been a MacOS user now for almost 7 years, before that 10 years of Linux).
[0] https://folivora.ai/
[1] https://www.alfredapp.com/
[2] https://iterm2.com/