Liquid Chlorine worked the best in my use case. Bought a house in Florida with no bathroom exhaust fan. Fought tooth and nail to keep it at bay. Squeegeeing the walls, apply after shower mildew/mold inhibitor. Nothing worked.

Liquid Chlorine did. Open bathroom window, placed a fan in front of it and sprayed down the entire shower heavily. Yes the smell I was powerful, I wore a respirator. It's been over a year and we haven't had it come back at all. We still squeegee and apply mildew/mold inhibitor and we now have a very high powered exhaust vent in the master bathroom.