For many of us, the mucus is a forever thing, whether thick or thin. Clear is a very good sign. For others, it indicates a coming flare up.
I have never, in 3 1/2 years, even tried to "get all the mucus" in any session. When I use the 7% saline, I cough for 5-10 minutes - when it subsides, I quit or I too would be at it 3 hours a day. My mucus is always present, but in greater amounts if I am stressed, don't drink enough fluids, have a bout with allergies or asthma...

As for that thick mucus, I have found a direct correlation between the amount of water, broth & herbal tea I drink and thinning it out some. My goal is 64-72 ounces a day. If I miss for one day, it is thick like honey - miss more than that it is like glue. I just brewed up a 16 oz mug of Breathe Easy Tea to have with my early lunch. I will have another with my afternoon break, and water in between. Means a lot of bathroom trips, but that is better than choking on mucus.

What does everyone else do?

Sue
PS I was looking at the Heart Association web site to answer a different question and found something that was in the back of my mind regarding your Afib - beta blockers are not the only available drugs to moderate heart rate (https://www.heart.org/en/health-topics/atrial-fibrillation/treatment-and-prevention-of-atrial-fibrillation/atrial-fibrillation-medications)
"Potassium channel blockers help the heart’s rhythm by slowing down the electrical signals that cause AFib.
Examples may include:
Amiodarone (Cordarone® or Pacerone®)
Sotalol (Betapace®)
Dofetilide"
Perhaps by using one of these you would be able to tolerate levalbuterol as part of you treatment regimen.