Problem Xiaomi phones drop data on H+


Phones Xiaomi mi mix 2, Redmi note 8 pro, telekom and orange cards, on both the data drops randomly only on H+, in a rural area. It works normally on 4G in the city. The download arrow disappears, only the upload arrow remains and I have to stop the data from the control center. When I turn them off, the data icon remains for a minute (time during which if I turn them back on, they don't recover) after which I restart them and go. The problem has existed for two years, it was also on MIUI 10 and 11 and 12 PDEMIXM (mi mix 2). Settings are default, global software. 4 different cards, two phones, two different operators, different original software, the common element is the brand...and I hope you don't come to the same conclusion that I haven't found this problem on the net.