We used Borax to move some pretty nasty mould off before an interior paint. For the really bad areas we added Tricleanium (another alkaline). Boil the kettle and add to give the water some heat, it helps with dissolving and application.
It worked like a charm and for double points, the new paint was still fine some 12 months later.
I used the same mix on the last boat as a wipe down over the interior with a micro fibre towel. Maybe once every 6-12 months ish? That was always satisfying. As much as cleaning a boat in the middle of some airless summer day can be satisfying