The way I understand it, there is one EM field and photons of various frequencies travel in that field: radio, microwave, infra-red, visible, ultra-violet, x-ray, gamma.
We are awash with EM radiation of almost all frequencies from the universe. A little 5G probably isn't our biggest problem.
Besides, this article is more about electo-static forces, and how, when you're very small, these are much more significant than the gravitational force, which makes sense.
EM radiation is defined by it's wavelength and amplitude. Whether it is from a 'natural' source is completely irrelevant in terms of the effect it has.
I guess humans have changed the mix of wavelength we are exposed to a bit. E.g. more RF radiation from phones and base stations. But I'm not sure how significant those changes are in the overall 'background EM fields we live in'.
We are awash with EM radiation of almost all frequencies from the universe. A little 5G probably isn't our biggest problem.
Besides, this article is more about electo-static forces, and how, when you're very small, these are much more significant than the gravitational force, which makes sense.