Of course we can, even HBCI still works, and you can even access your (German) bank account from within KMyMoney.

For the website, it's also easy, even with PSD2 you can just get a physical TAN generator.

I use GnuCash/aqbanking on Linux with a physical TAN generator myself to access my German bank account. The fact that this works is not up for debate.

My point was that you can't do it *without hardware attestation*. You can choose between 1. a smartphone with hardware attestation, or 2. a physical TAN generator with hardware attestation.