The great think about PSD2 is that it comes with a bunch of laws and regulators are generally good at making banks compliant. An API that's not working is a non-compliant API and banks get it. PSD2 came in to force in Sept, 2019 and 2 years later all the major retail banks in all EEA countries work have fully operational APIs.

One major limitation is that PSD2 only regulates access to payment accounts, but doesn't mandate access to credit cards, investment accounts, savings accounts etc. This is why screen scraping (to everyone's dismay) is still used - to "expand" what's possible with real bank APIs.