Ann: Westpac 2022 Full Year Financial Results Announcement, page-142

A fair bit of rewriting of history going on here!
Regardless of what you think of the big 4 it was well acknowledged that the strength of our banks and the quality of their books put them in much better position than banks in many other countries that went full on into boosting earnings through the subprime market leading up to the GFC.
As has been mentioned our smaller banks did not enjoy such strength and had some real issues!
(The Recession of the early '90's was a different proposition and Westpac certainly had some wobbles after a number of problems)
The GFC crisis did however create global liquidity problems and the RBA stepped in to provide funding including accepting securitised packages of high quality assets to keep our banks going.
The Government of the day of course became involved later in regard to Guarantees as it became a worldwide practise so little option, just how it was structured which changed a couple of times. The Guarantee in regard deposits was to bolster consumer confidence and ensure an unwarranted run on the banks did not occur in light of what was happening elsewhere (market fear).
It should also be noted that the Guarantees provided by the Government in regard to wholesale funding did not get one call so in effect did not cost a cent and earnt the Government a decent wad of cash.
(Of course capital requirements for banks around the world has increased significantly since those days which also changes returns!!)
Anyway, I would recommend a quick read of this AFR article from 2018 where management of the RBA at the time (people like Glen Stevens) detailed exactly the role they played. I hope some find it interesting, puts a lot into perspective I think:-
https://www.copyright link/world/revealed-how-the-rba-kept-the-banks-afloat-with-a-4-billion-daily-lifeline-20180903-h14v38