I don't think the fine is automatic like that, it's more if you don't have an appropriate mechanism to manage it. In other words you need a content policy that is enforced.

A mod who deletes nude pictures is probably enough to not get fined.

I think the real issue is what I just said... "probably enough"; that's the real problem with the online safety act. People are mostly illiterate on the law, and now asking them to understand a complex law and implement it (even when the actual implementation is not that much effort or any effort at all for well run spaces) is the real issue.

As far as I am aware, 'probably' is about the best you can do, since the OSA is so vaguely defined, it's actually difficult to actually know what is and what isn't valid.