Does Germany not have fast bank transfers? In the UK, people used to use PayPal for this until the Faster Payments system came in, which meant that you can instantly transfer money to anyone with a UK bank account via your normal banking app.

I think it technically takes 24-48 hours to clear, but that doesn't tend to be an issue in practice. You'll get the push notification telling you the money has arrived and your balance will update in seconds.