New Random rebooting mi8

[Egorasik]

Hi guys. I've got a mi8 and I've been here and earlier on the forum. Also, I've got the most annoying problem I've ever seen - my phone can reboot itself after 1 minute of an activity or after 10 hours after hard working. So, here's my question - did I flash the Rom wrong or is it a soft problem/hardware problem? Ave devs!

 

[Egorasik]

Problem remains after I did the full wipe in the recovery (didn't touch persist). 8.8.30 by me, Russian language as a system language.. Magisk works too.. Actually, that's all I can tell you. Maybe I should reinstall everything with a help of the fastboot?