Is there a shortcut to undo MacOS's spell check correction without completely disabling it?
Solution 1:
Right after the wrong word pops up, just type Control + Z.
This will undo the 'incorrect' spelling and put the original spelling back. I've used this in Catalina, Big Sur, and it works on the Monterey developer beta 2 (so far).
There's no need to use the mouse or trackpad.
Solution 2:
Backspace or otherwise move the cursor back to the end of the word & it will show you what you actually typed instead. Click to accept.