Re: Why not use 4G/5G?
Addendum, as I finish writing that comment, I finally found this document that spells out the limits that various different regulatory bodies are planning to place on unwanted emissions (UE) into the 23.6-24GHz band, and it looks like the EU is being much more strict than pretty much everywhere else on the planet, and the US is most lax:
African Telecommunications Union -28 to -30 dB
Arab Spectrum Management Group - 28 dB
European Conference of Postal and Telecommunications -42dB
US FCC -20dB
Asia-Pacific Telecommunity -29.7 dB
Most of these seem to be proposed limits, not set in stone yet, but it's worth noting that the Asia-Pacific Telecommunity includes most of the countries where 5G modems will actually be made.