Which is not very open, it just means it's open to other companies. If I want my own data there is no api for me.

Open banking isn’t mandatory. Psd2 and successors are. But it does not require the banks to expose feature parity APIs so others can replicate their apps.

AFAICT, psd2 should be sufficient to do the most elemental of banking features. See transactions and initiate them.

But that is quite limited.