5G doesn't imply a frequency. For example, in my region 5G non-standalone from T-mobile uses a 20 MHz band around 630 MHz. That's even lower in frequency and with better propagation than most bands chosen for 4G LTE.
5G modulations themselves improve upon 4G LTE standards by about 15-20% hertz for hertz. That means that in order to get more speed they can't use the same amount of spectrum. For >20% improvement they need to use more of the electromagnetic spectrum. That usually means using higher frequencies that don't propagate as well. But it is nothing intrinsic to the 5G modulation.
5G modulations themselves improve upon 4G LTE standards by about 15-20% hertz for hertz. That means that in order to get more speed they can't use the same amount of spectrum. For >20% improvement they need to use more of the electromagnetic spectrum. That usually means using higher frequencies that don't propagate as well. But it is nothing intrinsic to the 5G modulation.