Ah, if the aircon and exhaust fans aren’t common property, then your next step might be to follow Kaindub’s advice and issue an APVO – but since that didn’t work in the past, it’s unlikely to work now.
I think the fact that this individual has targetted several residents in the building previously may justify Owners Corp action. It’s not mandatory but no one will go to the tribunal if the OC contributes to legal fees.
Perhaps a writ for damages of tens of thousands of dollars might put her gas on a peep. I’m not saying you’d win such a case, but maybe the threat of having to pay a lot of money to defend it and potentially more if she lost might put her back in her box.
That said, if we are talking mental illness here, logic may no longer apply.