Confused about saline

I was diagnosed with bronchiectasis and MAC and am relatively new to this whole battle. I have a constant cough which is much worse at night but no shortness of breath. The mucus I cough up is pretty thin. I have ordered a wedge to elevate my upper body at night and am praying it will help. I was also told I am allergic to dust mites. My nasal drip is pretty bad at times. I am taking an antihistamine.

I repeatedly see mention of 7% saline nebulizer treatment. Does this help with controlling the MAC bacteria and curbing cough? I have asked my pulmonologist about saline with this response: "I don't generally use 7% saline. I use mucomsyt mixed with albuterol to thin the mucus, along with the vest. If this does not work, then I use dornase. "
I am not asking for medical advise but am curious to get your take on this.

At the present time I am using the compression vest 2x per day.
I have a Rx for Albuterol Sulfate, 0.083% for nebulizer. A respiratory therapist (who taught me how to use the compression vest) who said it would not help with cough and she did not think it was necessary.

I am confused and trying to keep the faith that I will find what works. I appreciate your feedback.