

The bank doesn’t need to manually support GrapheneOS, the app just needs to behave appropriately - which, as you can see from that list, the overwhelming majority of them do.
If my bank stops supporting it, then I will move banks. But I doubt it will ever really become an issue.
you’re misinterpreting that list, it is not exhaustive - it’s a list of banking apps which someone has tried and updated the list. the lack of a specific country or bank on that list doesn’t mean it doesn’t work, it means nobody has tested it, or nobody has added it to the list, at least