The harm may not be from radiation, but from backlight, vibration, sound of messages. From them, the dream becomes bad. And lack of sleep is already bad for the body. Turn off the gadget at night and sleep next to it as much as you like.
Once I studied at the medical academy. On a biology class, the teacher talked about a study conducted by some biology students on the topic of invisible harm from various gadgets. They set up an experiment: they grew onions (and onions are the most typical subject of various laboratory biology) near the gadget and fenced off from their influence and compared the state of the cells of the bulbs. So, the cells of the bulb growing near the gadget were more damaged (even mutations were observed during cell division), in contrast to the bulb that grew isolated from such influences.
I can’t vouch for the truth of the experiment, I’m just telling you what I remember.
Also in my memory came up info about the doc. a film dedicated to people who are very sensitive to any impact of any electronics, gadgets, technology (in general, any waves emitted by such objects). This is considered a disease (I do not remember the name, I saw the film for a long time) and such people live in places far from various waves.
At the moment, no harm from electromagnetic radiation to humans has been found, at least to the extent that we are exposed to it. There are standards for permissible EM radiation for household appliances.
The world around us is stitched with EM waves - cellular communication, Wi-Fi, radio. Moreover, it has been sewn for a very long time - if there were negative consequences, I think they would have been noticed long ago, at least in large cities.
If you are still concerned about this issue, move your phone out of bed or turn on airplane mode. worrying about it in itself can probably harm the psyche.