Well that can be true but the drop off is down to frequency and much of 5G uses the same as 4G. However this will change when the higher frequencies come on line.
Currently the max freq of 5G, in the UK, is 4Ghz (less than Wi-Fi 5Ghz)
With 60Ghz and up to 300Ghz things will change as they will be absorbed by objects 5mm to 1mm, rain drops etc.
It is also worth noting the ground attenuation which is also relatve to frequency, similar to gravitational pull on photons.
For a basic guide see
Range can be calculated on this basis at high UHF and microwave frequencies when high-gain antennas are used, located many wavelengths above the ground. RF Basics: Radio Wave (RF) Propagation - EETimes