@Rose_Languste wow, you are amazing! Everything is working now, like I wanted with that wiring, like you described:
Only one thing I recognized now and forgot to say: When someone does ring at the entry door on the ground floor everything is fine.
But I live in a higher floor and if someone does ring directly in front of the door of my flat, then Nuki Opener thinks the same (that someone is ringing on ground floor).
Is it possible, that when someone does ring directly in front of my door, that I don’t get any notification of Nuki App and only the separate bell will ring? So it would be perfect, cause then I would have a different ringtone, when someone is already directly in front of my door. But is that possible?