wkearney99 said:
As has been said, 4G isn't going away any time soon. 5G requires much closer proximity of towers in order to gain the benefits of it. For densely populated areas it certainly has potential. But most places aren't that and will continue to have 4G LTE coverage for quite a while.
"5G" is not one "thing" but three different technologies on even more bands. Low-band 5G is an overlay of 4G on 600GHz, 700GHz, 800GHz, and 900 GHz with T-Mobile rolling those bands first, some of it acquired from the Sprint acquisition. Data can be slightly faster than 4G, sometimes, but coverage can be nationwide, just like 4G. So there is no closer proximity to towers. It depends on the frequencies, lower goes further with less capacity.
Midband 5G is at 2.5 GHz, 3.5 GHz and 3.7 GHz to 4.2 GHz. It's wider, so more capacity and faster speeds, but range drops. T-Mobile got some midband spectrum from Sprint also, and Verizon bought some at auction. ATT has been a bit slow with this band.
Then there is Highband 5G, sometimes called "millimeter wave." It is at 24 GHz, 28 GHz, 37 GHz, 39 GHz and 47 GHz. These frequencies are VERY line-of-sight, so range is short, but speeds can be fast. These are the fast 5G speeds you hear the carriers bragging about, but they are not common. ATT is using 39 GHz and Verizon is using 28 GHz, I believe. Think a few 1000 feet coverage, maybe a football stadium. Actually I think Verizon is in all the football stadiums.
Then there is Dynamic Spectrum Sharing which is another story altogether. Different technologies on the same band. Overall its a big mess, and unfortunately, it can't be fully described well in just a sentence or two, at least if you want to be accurate.
Really you only need 4G on a phone. Most of the 5G "tricks" only benefit either low-power IoT things on one end, or high-bandwidth hogs like PC's on the other end.
Now international? Yes 5G is happening there too but there are many frequencies, and your phone may or may not support them.