Cell modems are around 300 milliwatts transmit, it would be like holding a LED light up to your head that flickers on and off when sending data.

Extremely tiny exposure of non ionizing radiation, you probably get more from the monitor your looking at right now.

5G requires far more towers than 4G or 3G before it, and if biological damage is possible accumulated risk when measured over an entire population can still be problematic.

Ultimately this isn't simply an issue of "personal risk." If there's no danger, there's no danger. But if there is and you live in a major city simply not owning a cellular device may only lower your exposure.

None of what you say is false, but without numbers it's impossible to compare to other sources of danger. And like ionising radiation, you need to compare to background levels. How does it compare to, say, the sun? Or EMC emissions from motor vehicles?

(Yes, they're not zero: https://www.ofcom.org.uk/__data/assets/pdf_file/0029/44876/m... )

No it doesnt. It can work with more on 60GHz, or it can work with the same amount on the same frequencies as 4G.

And in either way - more towers, less power per tower.

Or in your pocket. Where do you carry your phone?

That would only apply to the phone transmitting, wouldn't it? The RX is broadcast from the nearest tower, and 5G uses beam-forming. If your device (or another device near you) is receiving from the tower then there's not much of a way to avoid getting exposure.

Not much way to avoid getting exposure to electro-magnetic waves?

You make it sound like EM waves aren’t being emitted or reflected by everything in the universe short of a black hole.

And cell phone EM exposure levels for someone who isn’t carrying a phone - hopefully this person knows better than to walk outside, or stand near a window!

Black holes still emit hawking radiation.