BTW, interesting that you mentioned Xiaomi since several people have reported exactly same issues on their Xiaomi devices in my country. Some user sent their phones to the warranty service but no luck even after changing the board. Temporary fix was to reboot device or use air plane mode for a while. But now people are reporting that leaving 5G out of preferred network type selection have fixed the issue for good. (If I have understand correctly 5G NSA uses LTE for sending data)
Probably this has nothing to do with Pro1-X but might be still good to leave 5G out of preferred network type s