I am STILL a gardener. I garden in Minnesota and deep South Texas. I discussed this subject at length with my ID doc. Here is what he had to say: "MAC and Bronchiectasis are diseases you live with, and you need to learn how. Learn to do what you love safely."
With his & my pulmonologist's blessing, I garden with precautions. Wet the soil/mulch before gardening working to settle the dust. Wear gloves, sleeves, pants and shoes. Take them off and wash them when you come into the house and take a shower. If you need to rake or otherwise raise dust, wear an N95 mask.
I hire out really risky jobs like pulling out big plants (sprays a lot of dust around) and dumping/spreading mulch or dirt.

As for house plants, mine are in pots deep enough to add 1" of gravel to the top to keep soil and spores from flying around. Water only when dry (varies for each plant - I use a moisture probe) and remove water from drip trays afterwards.

This strategy worked for me for asthma and allergies and continues to work now.

Remember, NTM is everywhere, you can't avoid it without encasing yourself in a sterile bubble. That is no life at all.

The point is to reduce exposure from the most pervasive and concentrated sources (like steam and mist from known NTM contaminated water.)

Then do your airway clearance to kick out the incidental germs you inhale... Everyone begins this journey thinking they have to avoid every potential for exposure. You need to learn what sets off an exacerbation for you, and then relax and keep going forward.
Sue