Google pixel devices have had this for years. It's one of the few things that keeps me glued to this platform.

Just push the button to go to the task switch view and as long as the window preview thumbnail isn't blanked out, I can just get the phone to OCR any part of the screen in real time.

Yup, I've used this for years. See also: not being able to select certain text without clicking a link (say, in a search result).