I am not familiar with Clear Lung.
As for NAC (N-acetyl-cysteine) you can look at https://link.springer.com/article/10.1007/s40264-020-01026-y
This is a review of NAC studies in several lung diserases, mainly reviewing safety, by citing the studies with links to them at the end of the article, which makes them easier to locate.

Here is my own tiny (2 person) observation - my daughter (age 41) & I each have bronchiectasis plus different types of atypical asthma. I have a history of MAC & pseudomonas, she a history of intractable asthma attacks leading to hospitalization. We were seeing different pulmonologists in the same group practice, then she switched to a new doc due to a change in insurance. All 3 recommended trying 600mg NAC supplements, which we did. Each of us has had only one exacerbation in the past year, despite having histories of 3 or more apiece for several years. No hospitalizations or need for antibiotic therapy. Neither of us has had other med or routine changes, except for needing much less nebulized asthma medication than in the past.

Other people in the MAC group who have reported using MAC, what has been your experience?
Sue