The tech will switch between the ideal frequency for the case. They're not going to use 50GHz for broadcasting through a neighborhood. It's much more likely they'd use that frequency for line of sight in an airport or arena.

There's studies from long before 5g was a twinkle in anyone's eye that show that 50GHz won't penetrate more than a mm of skin. This is consistent with the concerns of 5g critics who are worried that the higher frequencies will interact more with human tissue, as well as the law of conservation of energy. The more the frequency interacts with the human body, the less it can penetrate the human body because it's consumed in the process.

As I said, this is similar in concept to radiation. An alpha emitter will probably have every single particle that reaches your body will interact with your body, whereas a gamma emitter can penetrate but is less likely to interact with your body. The result is that generally speaking gamma sources are the scariest because shielding can only do so much, and the best protection against gamma is distance.