Yes, you are correct that bullets displace the air they travel through, doing a kind of… hydrostatic shock as seen in ballistics gel, but to the air itself.

When a bullet isn’t subsonic (is supersonic), that’s generally fast enough that it creates an audible snap or crack from the air pressure gradient shifting so quickly, basically a micro sonic boom… and with particularly large/fast bullets, that effect on its own can damage soft tissue, and as you say, be loud enough to cause hearing damage (over pressure).

It is possible the bullet did not actually itself physically touch Trump’s ear, and that this micro shockwave of air displacement, from the bullet just barely missing his ear by… maybe up to a few centimeters for a 5.56 bullet?.. is actually what caused the capillaries in his outer ear to rupture.

The math on that is a bit more complicated to solidly verify the plausibility of that idea, but, yes, I agree that what you are saying is generally plausible, based in reality and not wildly speculative.

We need to fix our now and future, not fawn over what could have been.

I entirely concur.