> Sometimes just breathing hard through my nose starts to make my ears pressurize and threaten to pop

I had something similar (ears permanently felt like they needed to be popped, for months). Was diagnosed with a deviated septum + allergic response causing my eustachian tubes to not regulate ear pressure properly. Flonase helped. But cluing in that it was partially due to an allergic response (deviated septum made my nasal passage narrow, allergies closed them all the way), I have found that Benadryl is extremely helpful with both nose breathing and preventing the issue with pressure in my ears. I only take it when I have difficultly nose breathing.