[deleted] I don't have the impression the OP is exaggerating. I would encourage you to assume that everybody here is acting in good faith.
Some banks are only available via their mobile app. Some others that do web banking, still require the mobile app as a security key to sign into the web banking.
If the OP can't get the app working, it might well be a case of either switching to a different bank or switching back to stock Android.
I would encourage members of this community to help with the problem faced, rather than questioning their issue.