How to paint a small bathroom with very poor ventilation?

Amateur here, just trying to do his best.

How to paint a small bathroom with very poor ventilation?

I imagine I’d want a paint that seals the paint behind it (which has been prone to a little mold), and one that is also mold/mildew-proof, right?

What type of paint/procedure is best for a tiny full bathroom that has very poor ventilation?