If the sub 6Ghz band, 5G is basically the same as 4G LTE, similar power levers (sometimes lower depending on some technical details beyond the scope I can go into here). But there are some significant technical improvements. A lower TTI, the TTI is the interval in which the modulation and coding schemes can change. In 4G LTE the TTI is 1ms, for 5G it is 100us. Also, the sub channels can effectively be smaller. The benefit here is to capacity. Think about protocols that may have small packet sizes, eg. Votle (voice over LTE, sort of like VOIP) or TCP SYN/ACK messages. If you devote an entire resource block (TTI, ie. time slice and sub-channel allocation) to a small packet you effectively waste a lot of spectrum. These are a few very simple examples of the various improvements that 5G in the sub-6Ghz has. But none of these changes to the protocols have any effect whatsoever on the effective radiation or would change the effects to humans which, in my view has been clearly been shown to be safe.
Now, the FR2 5G which typically operates in the mm-wave bands, for example 28Ghz. All of the above features and more apply, but one very important extra feature of the small wavelength is that it makes it possible to utilize beam forming antenna arrays, specifically Phased Array Antennas or Meta-material antennas. The reason is because the antenna elements (think each antenna element as a sort of RF pixel) has to be spaced 1/2 lambda (wavelength) apart so the physical size in the low bands is simply impractical but at higher frequencies the wavelengths are short enough that these antenna arrays are small (on the order of less than 1 foot square) and can have high gains and narrow beam widths. Now, if you think about this, that means that the beams are narrow (think about it like light, RF and light are both electro-magnetic waves but at different frequencies). This ability to control the beams means that the energy can be much lower. A joke that is often made in the industry is that mm-wave cannot propagate out of a wet paper bag. This is literally true, a wet piece of paper completely stops a mm-wave beam. That means that it cannot get through a pane of glass (or it is severely attenuated) and does not penetrate human skin, much less so than the lower bands. The benefit of the mm-wave is mostly that the antennas can be smaller and there is just a lot more spectrum. The benefit of more spectrum is of course Shannon's law C ~ B*SINR that is, the capacity in bps is proportional to the amount of spectrum B times the Signal to Noise and Interference ratio. So having more spectrum is a big deal.
All of what I am explaining here I am hoping, that the highly intelligent HN readers will understand is that the sub-6Ghz (FR1) 5G is essentially no different from 4GLTE except that there are a number of protocol and other improvements that increase capacity. In fact, the radios are the same in many cases and it is simply a software upgrade (many of these radios are essentially SDR's).
The mm-wave (FR2) is what is really radically different from traditional 4GLTE (although, it has been used for other wireless use cases for a long time such as LMDS, but that is another long story, in fact, much of the mm-wave spectrum comes from older LMDS applications). But newer technologies such as PAA (phased array antennas, borrowed from DoD military) offer significant increases in capacity and bandwidth at much lower and safer energy levels than previously possible from FR1 systems.
I know this is a very long post, but this is a very high level overview of the 5G technology. There are many other aspects and exciting new applications that are far beyond the scope that could be covered here. The most important issue in my view is that the fears and the propaganda that 5G has some sort of health related issues is founded in ignorance of the physics of the technology IMHO.