Getting a statutory appointment strata manager is one of those “Be careful what you wish for” situations, not least because the strata manager has to do everything by the book and you have lost control of your owners corp.
Much better is to first find the strata manager who will take over, and then vote at your next AGM (or general meeting) to delegate all the powers of the EC to the strata manager.
That means that at any point in the future you can rescind the agreement, and you can still have your EC and the strata manager can consult with them as much or as little as you wish.
But when it comes to dealing with the nasties in the building, the EC steps back and lets the strata manager get on with it.
The first thing you need to do is identify the right strata manager and they will advise you on how to proceed, including getting rid of the incumbent.