I remember back when my air hunger was worse, I would seem to benefit from some exercise, even intense exercise, and feel ok during whatever I was doing, like running. But then shortly afterward, the air hunger would return sometimes worse.

You mentioned about having well-controlled asthma. Did any medication dose change at all especially after Covid? I wonder if your level of exercise might be over doing it. You should definitely still exercise to your comfort level, but if your situation is like mine was, I had to taper down the amount and intensity of exercising I was doing. Going from running 2-3 miles in a day, to light jogging for maybe a mile, and incorporating mild weightlifting 3-5 days a week. In fact, the weightlifting seemed to benefit my breathing the most; I would life weights without pushing myself and my air hunger went down quite a bit. It seems you do a lot of cardio, which at some point might have diminish returns. A suggestion would be to replace 1 or 2 cardio sessions with mild to moderate weightlifting with controlled nasal breathing and see if that helps at all. What do you think?