Thanks for the updates, as looking into eight website they only stated support China Unicom, China Telecom. Did not know it also support China Mobile, always good to check with user experienceMy wife is using it now in Guangzhou China. As per her, it is quite okay. No 5G connection though, only 4G connection to either China Mobile or China Unicom in Guangzhou.
She told me that had no issues using WeChat Video calls with my mum-in-law in another province, including a recent one for one hour.