The short answer is I don’t know, but if I read your question correctly I suspect the answer is “not much impact, if any.” Cell transmission towers would be dangerous at close range, but cell phones themselves would be like flashlights as you say, but not bright ones, and probably not noticeable at all, except at very close range. They’re not listening to these frequencies.

I would think it perhaps analogous to ultrasound. Our electronics are giving off all sorts of ultrasonic noise that we can’t hear (but sometimes annoy dogs and millennials). We have ears capable of hearing, but not at those frequencies. But you could nevertheless expect hearing loss if you put a 1kW ultrasonic beacon right next to your ear.