I remember going through something like that with Plaid. That one actually asks for your online banking password, it's not using some API access... very bad.
I had to convince it that it didn't recognize my bank to eventually put in account numbers rather than give it credentials to your bank's online account. I think I put in the wrong routing numbers to get to that form. Definitely a bad experience!
I am curious if people with your attitude think it is OK to try and be sneaky to trick users like that, or if you are not aware that is what is happening?
It just seemed weird that GP described this whole ordeal about how to couple accounts, and then glosses over any process after they found their account number. They have edited their post since.
The second ‘attempt’/flow allowed me to enter my IBAN. I will change my original comment to reflect that.