Thanks for clarifying! I understand the architecture but perhaps didn't explain it properly in my comment.
It does honestly strike me as the best approach given the constraints, but here in Canada almost none of my banks are supported with OAuth flow last time I checked so giving the 3rd party providers my credentials and having them log into the bank both violates the TOS of my bank and is also far less secure than I'm comfortable with. Storing my financial details in YNAB / their partners is one thing, storing credentials that can be used to actually move or spend my money is another.
It's honestly not a huge deal for me personally. Entering the transactions manually is a good habit as I can see the balances update and mobile app is easy to use right on the spot.