Turning LTE on was a good idea. It will affect the way the phone handles mobile data connection.
You can also try using WiFi only (turn off mobile data). If the problem doesn’t occur then it’s likely to do with mobile data.
My thoughts: if geographically you are between two masts the phone may “hesitate” and this might cause problems.
Does the problem occur when you’re at a specific location or doing a specific task?
It happend again I think it has always happened when I wasn’t at home, so I was always using mobile data, but other than that no specific geographical location. Today I will write to the support team and let’s see what they will tell me
If that is the case ensure you have wifi off in case it’s trying to find a better connection and switching between wifi and network.
Also you can try Settings > Network and Internet > Mobile network > Advanced > Enhanced 4G LTE Mode : OFF and Preferred network type : you can try 2G/3G only and see if that is any different.
Probably, I’ve downloaded an app that alerts me when battery is over 35° and it doesn’t stop alerting me and I’m also currently using 2 SIMs (the main one has like 4 years) so there could be several reasons but they’re all quite temporary so I hope it will stop when I’ll get back to a colder place with using dual SIM