GHz are Giga Hertz. One hertz means one vibration per second. Giga means 1,000,000,000 vibrations per second.
The more vibrations per second, the more energy an electromagnetic wave so x-rays have far more energy than microwaves
In fact an x-ray vibrates
1,000,000,000,000,000,000 times per second!
(And blue light around 1,000,000,000,000,000 times)
So it sounds like a lot, but compared to xrays it’s not! And then you have gamma rays and they are even worse than x-rays (and One of the the reasons Chernobyl was so scary but I’m not expert on nuclear stuff so I’ll leave that to them)
But all this radiation is part of same spectrum. And 5G radiation has a lower frequency (and thus lower energy) than even visible Light, let alone UV, X-ray or gamma.
Have attached chart from NASA which probably summarises what I’ve said in far clearer and succinct way.