Question about Google Nest Mini Gen 2

In my opinion, there should be an electrical spark somewhere in the new flat, such as a light switch, relay, contactor or similar.

Troubleshooting would be ideal if 2 identical devices are available. If both crack, it is not due to the devices, but possibly to the network or the Internet connection. If only one device cracks, there is a fault in the device.

By the way, a second device enables a quite decent stereo sound...