Focus navigation via external keyboard and mouse (or Gboard) in Android

I was wondering whether there is a way to configure the phone for accessibility needs to reflect the spasm pattern and attachment characteristics of people whom may bee affected by spasms and or autism, and may be unable to handle Gboard for input and may require navigating the screen through Kensington keyboard (or other type of keyboard for mobile phones and tablets). Ideally, there would be a way to navigate user interface elements though the hardware keyboard's key up, down, right, and left keys, and a green square highlighting the software element highlighted should be displayed. The element can then be clicked upon via the external keyboard, or external mouse. Is this, currently implemented, in Android (and, if not, when will it be implemented)? It would be nice if the arrows and ability to mouse click were also available in Gboard, for reference, and debugging (by users that did not have access to the external keyboard, and wanted to debug that behavior). Thanks.