Maria Hi there 👋
You can follow indication at this official bunq 🌈 document:
https://together.bunq.com/d/43452-german-ibans-hello-germany
I have a Dutch bunq account with all NL IBAN and it took literally 2 minutes to get a sub account with DE IBAN set up and running.
If you open a brand new account as German resident, you should get a sub-account with DE IBAN since the start. If it does not happen, please contact bunq support from within the App.
Have fun ☀️
GG