I decided to do some research on the topic and found these two articles listed on google scholar (i have the PDFs, and can share them if you tell me how to!).
https://www.sciencedirect.com/science/article/abs/pii/S1438463917308143
https://www.sciencedirect.com/science/article/abs/pii/S037842742030028X
As the papers claim there are real considerations to be had before trying to implement 5G as it is planned. Most of the issues mentioned with (non ionising, non visible) electromagnetic field radiation however, as I understand, are that
There aren't enough studies of EMF radiation on real-life-like environments to really reach a conclusion about the subject, BUT the results obtained in controlled laboratory conditions should be worse in day to day exposure due to the combination of different wavelengths and other toxic stressors.
The size of the subjects often used to conduct such experiments (birds and rats) would produce results that are not so easily scaled up to a bigger body (such as ours). And there's not enough studies around the subject of EMF on the skin, or the systematic damage that could result of that.
The radiation density of a functioning 5G grid would be massive compared to previous generation implementations of wireless communication, and that could be dangerous, considering there's some evidence of EMF radiation at least contributing to non communicable diseases.
There are clear agendas at play when studying the topic (not playing into conspiracies here, just according to one of the papers), and you could expect that some of the studies available are made with the explicit purpose of showing that there is no danger in EMF radiation. It seems that it's as easy to find a study to say that, for example, there's no correlation between non communicable diseases and exposure to EMF radiation, as it is to find that there is.
Even after reading both papers, I still don't feel convinced of the potential harms of 5G, and I'd like to know your opinion. It's been pointed to me already that Kostoff's paper is somewhat conspiranoic, but no similar feedback has been shared, to my knowledge, on Di Ciaula's review of the literature.
(I've already read the answer available here: Does 5G pose health risks?, I want to know what you would say about these arguments in particular)