Welcome to Mayo Connect. It seems overwhelming when we first get this diagnosis, but trust me things do get better over time.
I'm going to try to answer several of your questions, but would invite @poodledoc, @irenea8 and other "veterans" to weigh in with their experiences.

First, the vest should be a help with airway clearance, but if you are trying to avoid the antibiotics, I would suggest that you also ask about nebulizing 7% saline, which has the dual advantage of thinning mucus and potentially suppressing the bacteria growth. Here is an article to introduce you to it:https://smartvest.com/blog/airway-clearance-techniques-for-bronchiectasis-and-copd/

Second, most of us were told that outdoor pools are safe. Chlorine does not kill MAC so it lingers in the copious water vapors above an indoor pool or any hotub, so these are to be avoided.

Finally, not everyone experiences hearing loss from the drugs - I got my a baseline hearing test, then was tested by an audiologist every 3 months to be sure, since I already have issues with tinnitus and age-related loss. So if you need to start, just be hypervigilant.

If you spend some time reading other discussions in this support group, you will find the answers to many of your questions.
Sue