Also remember the Strata Manager is probably managing up to 100 Strata Plans and is therefore juggling the constraints of the Act and the whims of maybe a thousand owners for when they would like to have the meeting. There are only so many hours in the day.
If you are looking to terminate you should be identifying a replacement as soon as possible and formally requesting that an appropriate motion be added to the AGM agenda. You can’t terminate until it has been put to all owners at a meeting with the requisite notice.