The advice from the United Kingdom National Health Service appears at the link below:
https://www.nhs.uk/conditions/mobile-phone-safety/
There appears to be no conclusive evidence as to whether radio-frequency waves can cause cancer. A decade ago parents taking the children to school were getting very concerned about mobile phone transmission masts and mobile phones. Today parents are the culprits for introducing mobile phones into school playgrounds, and the mobile phone masts are still there but are often disguised as lampposts.
The reality is that radio-frequency waves are everywhere nowadays and there is a new fanaticism about the dangers of smart metres.
Early in my career I was a radio systems developer and worked in a radio laboratory. The important thing to know about radio is that the power of the signal is strongest at a position very close to the transmission source. The power field strength (the measurement of the strength of the radio signal at a distance) falls off very quickly as the receiver moves away from the transmission source.
Personally, I would never put a radio transmitting device very close to my head: I would use earphones or a speaker. Once small transmitting devices are a metre or so away from the body they are unlikely to have a significant heating effect on the body.
I probably have far more than a hundred transmitting devices in my house: e.g. gas smart meter, electric smart meter, router, four mobile phones, three cordless phones, Sky Q box, Sky Q mini box, two Sky Q boosters, a meshed WIFI booster system, Bose speaker, two tablets, microwave oven, a variety of metering devices, radio controlled lights, printer ... If you are going to protect yourself and others then a full and informed audit is required. Switching off the mobile phone may not leave you free of radio signals.
