AFAIK cardless atm transactions only work with local thai accounts and their apps. Whatever card you bring from overseas can be eaten by then ATM. happened to me too at BKK airport, but a woman from kbank came and opened the ATM after 10 minutes. Another option would be bitcoin/crypto and sell them for thai cash locally. No limit in cross border transfer.
I guess I used them too, before covid. North side of the moat, right? They did tm30 and residence certificate in a few days for me. The license I did alone, took 2 days.
You can actually activate the app yourself at the kasikorn atm. Be aware you need the passport number of the passport you opened the account with. It changes with a new passport every 10 years.
German Passport, right? Everyone in the IT knows, that you don't use ambigious symbols in codes that have to be read and typed like wifi passwords. No 0O 1l 6b etc. But for the german government thats "Neuland"