I think each of us has had a different experience with MAC & bronchiectasis.

In my case, I saw both an ID doc, who managed my meds, and a pulmonologist, who manages my lung health. It was extremely helpful because they functioned as a team, and kept my primary in the loop as well.
Now that I have been off the antibiotics for 3 years, I continue to see the pulmonologist (first every 3 months, then 6 months, now annually unless I get worse.

As for bronchodilators. my pulmonologist has transitioned my from (inhaled and/or nebulized) levalbuterol plus budosenide as needed to a (generic) Symbicort inhaler, which has calmed my tremors a great deal. It has been the BEST management tool for my combination asthma and bronchiectasis. I made it through allergy seasons and a respiratory virus without a major exacerbation for the first time in probably 10 years. I also neb 7% saline and do airway clearance (Aerobika) to keep the NTM at bay.

As for the O2 sat question - hmm... I personally have wonky O2 sats - probably due to a lifetime of lung issues so have never considered this. I think the better question, if you are dealing mycobacteria, is "Are you keeping your lungs clear of mucus by doing regular airway clearance?" If you are able to do so without albuterol, maybe ask the doc about 1)stopping, 2)stepping down to a puff on an inhaler, or 3)substituting a less tremor causing med like levalbuterol or Symbicort.

Are you doing airway clearance regularly? Do you use saline nebs or a device to help move the mucus out?

Sue