It's not Zigbee, but I've been very happy with Yolink and several of the products in their ecosystem.

I seriously looked at yolink for fridge/freezer sensors, but just couldn’t stomach their pricing in Canada. (e.g. the Local Hub is 200 USD in the US, or 285 USD in Canada.)

I ended up with some Ecowitt (hardware sold under the Ambient Weather brand in the US) sensors and they’ve been working great for some months now. (900mhz RF has good penetration and the sensor hardware is generally appropriate for -20C operation.)