Please see suggested steps by one of our happy client:
Steps that were needed to activate the eSIM:
1. install on your snartphone Wear OS and Xiaomi Wear (could be China version if used or bought in China),
2. pair your watch with your smartphone using Wear OS,
3. open Xiaomi Wear and synchronize with your watch,
4. open on Xiaomi Wear eSIM manager (mobile network) and flash the prepaid eSIM QR code (bluetooth must be open on the watch and smartphone, international data roaming ON, Wi Fi ON)
4G will start automatically and after unlocking the eSIM the signal strength of the cellular antenna will appear on the Mi Watch display.
It was hard to flash the QR code. I have repeated this many times.
My phone - Samsung Galaxy s9+