which is basically the same thing as sunlight.
Except for the different classifications and therefore effects of different frequencies. X-rays and gamma rays aren't quite so safe (same sort of wave, different frequency). UV is a lot worse than wifi for sunburn...
I do a lot of non-ionising radiation safety stuff at work. It is well documented and researched, although there are still few long term (several decades) studies. We've been bombarded with this sort of stuff since radio and TV were invented.
Stuff is safe within prescribed limits which are very cautious (occupational exposure limits are 10x public exposure, but still thought of as safe).
Blind/placebo studies on people who claim that they suffer ill health have all shown it doesn't make any difference. In one case, people who claimed to suffer were invited to a retreat. After a week a mobile phone mast was placed outside and they were told it had been switched on. Some folk got hospitalised, their symptoms were so bad. So after another week they told the test subjects that the mast was switched off and everyone suddenly got better. Of course, the point at which they said it was turned off was when they actually switched it on...