Miriam
If you are having physical symptoms from the MAC, it is most likely time for treatment. The doctors have to tell you all the scary stuff about treatment and you may be more likely to hear from the people who have had problems with the medications. I have been on treatment for over two years and it has not been easy- some side effects, lots of doctor visits, labs and general inconvenience but it has not stopped me from functioning and living normally. I suspect your symptoms would improve with treatment and you could even be one of the lucky ones with a good response and few side effects.

You and others might be interested in a recent article which suggested that the time it took for cultures to grow MAC was correlated with the bacterial load in the lungs and thus the need for treatment
https://www.atsjournals.org/doi/abs/10.1513/AnnalsATS.202107-765OC
Their cut off was 10 days - shorter times predicted need for treatment. e.g. I was at 4 days when I started treatment and now much longer or negative. If you have this information about your cultures, it would be another piece of data to consider

Good luck and make sure that if you start treatment you start one medication at a time to let your body adjust and to tell which is causing any side effects. Also, expect that the GI side effects and fatigue will be worst in the first month or two but often improve after that