It's already done, sorry - those who can read have an advantage. You only have to reset the WLAN on the device itself (press the cleaning and dot-cleaning buttons simultaneously for three seconds).

Another important point is that the Roborocks can only use 2.4 GHz networks. In my case, only 5GHz networks were used, which is why I only had to set up a separate 2.4 GHz SSID for IOT applications such as the hoover and the Dyson fan.