Yes, much. The SAR limit was tested on an artifical head filled with salt and sugar based on a 6’ 1” 210 pound military man. The scientist who conducted this study later refuted his work as inadequet. But the FCC still uses this study as a RF and SAR limit to this day, despite the many newer studies showing biological effects much, much lower to the contrary of the older study, this does not even take into account non-thermal biological effects.

Bluetooth is safer than wifi in 2.4ghz or higher but it depends on the amplification and concentration of said signals. DECT phones are horrible, replace with corded phones. And yes, a head set is important. RF by the WHO is considered a class 2b carcinogen. Certain frequencies used and the concentration of these frequencies are even higher up on the classification list.

RF is ESPECIALLY dangerous to babies and kids. Do mot leave your kid near a cell phone. Their heads absorb hundreds pf times more radiation than someone who is 6 feet 220 pounds. But don’t tellvthe fcc that.