The Owners Corporation (i.e. you and the other owners) is entitled to whatever information it regards as necessary to make an informed decision by way of a vote at the AGM.
You and like-minded Owners need to sign a letter to whoever it is that’s convening the AGM, likely the E/C Secretary or the Strata Manager, and tell them in order for any Motion on proposed major works to be properly considered, that you require “decent, understandable plans and quotes” (and indeed anything else that you deem necessary) to be provided to all Owners together with the Agenda.
If that’s not provided, then you and others in attendance at the AGM can again vote the proposal down – but be mindful of the need for like minded Owners to attend the Meeting and of the need to be mindful that Members of your E/C may have gathered sufficient proxies to ram through their project.
Finally, depending upon the nature of the proposed major works, anything that could be regarded as an alteration, addition, or change to the Common Property needs a vote in favour by ≥75% of those in attendance at the AGM (incl. proxies), with that percentage determined by units of entitlement (a “poll vote”); that’s a Special Resolution as opposed to one determined by a simple majority.