Is the Xiaomi Thermostat (the one with a display https://www.gearbest.com/robot-vacuum-accessories/pp_1306883.html ) supported by the smartthings hub ? It looks like it uses Bluetooth rather than zigbee.
It’s actually WiFi.
It could work if someone wanted to write the device handler for it.
In the mi.com web site it specifically mentioned about it needs a compatible Bluetooth device in order to remotely monitor the temperature, e.g. the Xiaomi lamp and Bluetooth bridge or so
I believe it’s actually bluetooth, which piggy-backs onto either a Xiaomi bedside lamp or more recently the 1080p camera to utilise their wifi/zigbee capabilities.
Here’s a good explanatory video https://www.youtube.com/watch?v=q-VYxZtR-Dg
So i’m not sure if you will be able to integrate into smartthings, unless maybe secondarily through the lamp or camera (if that has a DTH)