Have audible alerts emanate from approximately the direction of the obstacle(s) when parking.
I’ve had a scenario where I was reversing alongside a wall, causing the proximity alert to sound (and display). I had to ignore this sound as I was aware of the wall and moving parallel to it, so it wasn’t a problem. As I reversed further and approached an obstacle behind the car there was no change of the audible alert and I hit it!
(lightly edited by moderator)