Would it also work with this transformer?
Netatmo Smart Video Doorbell Adapter (WLAN)

I wouldn't recommend batteries, because then you can hire a doorman right away.

Ganz normaler Klingeltrafo https://www.amazon.de/gp... und auf 24 V klemmen.
Also Klemme 0 links und Klemme 24 V Rechts.

The Aqara G4 can be operated via cable with a voltage of 12-24V AC or 8-24V DC as well as via six AA batteries. The bell transformer sold here can output 12V AC, which should be sufficient: Hager bell transformer

A degree in electrical engineering is not necessary, as battery operation is also possible 😉