@Stefan-Lime-Akita-3397131654#163307 We were talking about exactly the same thing. PSD2 X2SA is not an API standard, just a regulation (that bunq complies with, btw). It only demands there to be an API open to PIS and AIS that they can use to get certain information about a user's account and create payments on behalf of the user, depending on if they're a PIS, AIS or both. But there's nothing in the PSD2 that tells a bank on how exactly the API has to be structured, only that there has to be a way to these things. In case of bunq, their API can be used by every PIS and AIS out there, and also in addition to that by other users and developers, so they exceed the PSD2 regulations by far.
As you stated "Open Banking Europe has been launched to support Payment Service Providers (PSPs) and Third Party Providers (TPPs) in meeting the Access to Account (XS2A) requirements of PSD2". Many banks didn't have any APIs or didn't have APIs that were powerful enough to meet the PSD2 requirements. Therefore, they were looking for solutions to do so and some of them chose to go with the Open Banking / Preta standard. Some others went with other standards (Berlin Group etc.), and some built their own APIs. In regards to meeting the requirements of PSD2, it doesn't matter which standard you adhere to or if you adhere to any standard, your API just has to allow a PIS and AIS to do their respective actions in regards to user accounts.
Maybe you don't like that, and I also think this isn't the best outcome, but that's what PSD2 is. So if you want bunq to adhere to a standard like Preta or Berlin Group, then sure, that's a fair request to make. (But might also have some downsides that I mentioned in my previous comment.) But somehow suggesting that bunq is not meeting PSD2 requirements with their API is pretty far-fetched and not true as far as I'm aware.