Excessive mucus production in the upper respiratory system and throat.

Good Afternoon, I'm looking for some treatment advice for my post covid chronic condition. I had covid Jan 2021, I was put on a respirator twice that year ( first time for 9 days, second time later that year for 5 days). My lungs were scarred and damaged by covid and my capacity has diminished to 46%. I developed a cough due to excessive mucus production that always occurs in the morning and randomly though out the day. The coughing fits will last 5 -10 minutes which can include a sense of drowning or a gag reflex. I am not able to identify a common trigger for these fits with the exception that bending over for a period of time or physical exertion can be a trigger. The mucus produced is clear with bubbles and there is no pain associated with the cough. I been tested for allergies, acid reflex, have had the Clarifix and Rhinaer procedures done (that was a waste) and have been prescribed many nasal sprays . I have seen 3 ENT's, 2 pulmonologist and my Primary so far with no relief. I'm finding the medical community I have encountered are unable to help me manage this chronic condition. I see many on you on this support group have a similar lasting condition. I'm hoping for some insight on a treatment you have received that has relieved your condition so that I can make suggests to my doctors. Thank you in advance for you information, John Porter