As my opinion, MZ1 is amazing idea and I am looking forward to get updates of FW but here is one missing feature.
All ZigBee sensors are battery powered and it was a huge surprise that there is no battery status for such sensors in the app 3r-matter and Google Home does not show the battery too.
It looks the bridge does not bridge battery status yet.
I tested 2 types of sensors, window/door sensor and PIR sensor from different vendors.
Battery level is an essential feature for me and stopped me to move all house to this bridge 😞.
Please update your 3R-Installer app to the latest version, remove and re-install the batteries of the Zigbee device, then check the battery level in the device page of the sensor.