Whether the items are owner or OC property is irrelevant.
One owner is being harassed by another owner.
That is not a strata issue, it’s a person issue.
Note, there is no such thing as an enforceable cease and desist order.
Having dealt with something similar, my recommendation is that the affected person apply for an Apprehened Personal Violence Order. (APVO).
In NSW you can apply on line. You need to have some evidence ( diary notes, emails etc) to support your case.
I would then recommend to get a lawyer to represent you. At the first appearance in court, usually within three weeks of applying, your lawyer will apply for ban interim order till a hearing date is set.
If the offender breaches the interim order, it could lead to arrest and jail.
Of course it’s the affected person who has to front the costs. But what is peace worth?