Command+TAB (⌘⇥) to switch to most recent window (even on different space) The default behaviour of ⌘⇥ is roughly the following:


Switch to the most recently used app.
Bring all windows of that application (in the current space) to the foreground.
Give the most recent window focus.
Is there no window of that app on the current space? Switch to most recent used space with that app.


Say I have two windows of the same application open. One is running full screen in a separate Space, while the other is on the Desktop Space with other application windows. Take for example the following spaces:


Desktop: Safari + Mail Window  1
Full Screen: Mail Window 2


So now I'm working in Mail Window 2 (Space 2), ⌘⇥ brings me to Safari (Space 1). However ⌘⇥ again and I'm taken to Mail Window 1 (Space 1), whereas I would've wanted to go back to Mail Window 2 (Space 2). In order to go back to Mail Window 2 by keyboard, I have to go through all spaces using ⌃→ or ⌃1..⌃9, which is cumbersome when working with more than 2 spaces.

Is there a keyboard shortcut I'm missing, or a way to change how ⌘⇥ could work for my use case?
There is the default shortcut ⌘` (that's a backtick [or ⌘` for QWERTZ keyboard layouts] to toggle focus between application windows.

I don't think it's possible to adjust the behaviour of ⌘⇥ so it meets your criteria.