I inspect my girls daily coz I live in an area that has notoriously high humidity in Summer. If I see mould or boritis or what ever it’s called, I don’t throw the whole plant out, I just cut out the areas that look suss. Like spider mites, once you know what you’re looking for you can spot it really early. The secret is vigilance. Well I think it is.
I treat plant mould like cheese mould. Cut away the affected cheese just a bit further than the mould growth. Then give her a good wash in the citrus mix, your plant not your cheese. With the cheese grab some crackers, and pour a wine
Thankfully I’m now in a mould free grow zone.