[Elsie]

T_mobile already has a nation wide 5G network in place.

 

What a deceptive sentence!!

 

T-Mobile 5G cities: Where you can get it first

T-Mobile actually had some 5G coverage before December's nationwide 5G launch, using millimeter-wave technology to bring service to a half-dozen cities.

Atlanta, Cleveland, Dallas, Las Vegas, Los Angeles and New York have all had that 5G coverage from T-Mobile since the end of June, and you could use Samsung's Galaxy S10 5G to connect to the network. 

 

[orinoco]

T_mobile has been running TV ads daily stating they are the only company that currently has a nation wide 5G network.
I have no reason not to believe them.