MacOS is pretty good, it's a proper Unix system. Emacs works well, tho there are some eccentricities. Font size for example works very differently on Mac displays because there's a lot more pixels.

Open .config/emacs/init.el and get cracking. To get familiar with bindings and stuff, C-h t. The built-in elisp manual is also pretty good

I'm not suggesting the posframe solutions others have suggested also suffer from this behaviour.

Then what was the point of the rest of the comment?

Posframes (child frames) always display on top of the root Emacs frame. Modal dialogs like menu-set-font are OS windows which do suffer from the problem you mentioned... except for the vast majority of systems where they just display on the right workspace by default.

When I wrote hypop, I specifically make it find the workspace Emacs is on to summon the minibuffer window to. It's really not that hard at a small scale.

vertico-posframe makes a pop-up in the middle of the screen for completion specifically. This is probably what you want.

There's also my package [hypop](https://github.com/mitchmarq42/hypop.el) which separates out the whole minibuffer and hides it when not in use. It has a few major drawbacks and only works on the hyprland desktop right now so probably don't use it.