Zigbee sensor overestimates temperature by 3.9°C - how to calibrate readings?

Hello.
I bought a Zegbee temperature sensor and after connecting it, it appears to overestimate the temperature by about 3.9°C.
Is this normal?
How can this be dealt with apart from remembering such a misrepresentation? Is it possible to calibrate them?
Has anyone used such sensors?
What are your opinions about them?
Sensor powered by 2 AAA type finger batteries, new.




Photo of the Zegbee gateway. Connected via a network cable to the router.


Screen from the application.


I noticed another interesting situation. I unplugged the Zigbee gateway from the power supply. In the Tuya app, I got an "out of network" message on the gateway. The socket works, the sensors work. As if this notorious gateway was not needed for anything. You can clearly see in the screengrab.




Below a screen shot of the devices that are visible. There is nothing and they work.

I use such sensors in guest cottages and at my place they indicate the temperature well but I bought the ones that connect to the app via wi-fi. Yours probably don't need a gateway either.

A cheap NTC was probably used there.
Either replace with another ntc, or try to gently correct with an additional resistor.

Both options require some knowledge and skill.