Why and how does adult asthma develop after flu/bronchitis?

I have been an athlete all my life. I had a bad bout of flu with bronchitis last Feb/Mar (at the time not recommended to do covid tests) - stupid me, went out while sick to ride a fat bike and play hockey and my cough became bad bronchitis. Family history of emphysema/asthma, but I myself was "lucky" as I played all levels of sports (hockey/soccer/skiing/boxing) and have kept myself very fit and strong my entire life.

After this bout of violent coughing - over the summer I endeavored to get healthy (because of covid as well) and did TONS of cardio - way more than before... I wore a HR monitor and O2 sensor and everything seems always good. In fact, I find to be able to clear my chest once I get going. I ride mountain bikes, run, and can still do a sub 50 min 10K while being 200 lbs at about 11% body fat.

Problem is days I don't do cardio or lift. I find my lungs get "tight", and over the last 3 months, I've been sleeping on a recliner as I just can't breathe easily as the symptoms seem to come on at night the worst. I also find I am constantly clearing my throat (not coughing, however) and in the AM I find that my chest is FULL of super thick phlegm, like coughing out boogers. I went for a spirometry test and it was inconclusive as I am blowing out well within range. This is so frustrating. Some background, I've had probably 7-10 bad bouts of bronchitis in my 39 years, my brother/dad have asthma (dad now has COPD) and grandma died of emphysema and nobody was a smoker.

To get through things, my doc gave me a SABA and LABA (Albuterol and Symbicort) as per usual. Do they help? Yes-ish, but they don't seem to help with the throat-clearing/mucus collection thing I also have been doing this which helps: Applying pure peppermint oil on the chest/back, doing deep breathing exercises, still exercising vigorously, avoiding any inflammatory foods, and taking turmeric, pomm juice and Omega 3s. This is just getting frustrating and I have yet to see a pulmonologist as apparently I am triaged LOW and well. Covid has them all busy. I really need help 🙁