AT&T has announced that its 5G service is now live in 10 different American cities, Los Angeles and New York included. In fact, it claims to have 2 (authentic) flavors of this connectivity: 5G and 5G+, which are based on low-band and high-band forms of the new radios. They are available to personal and business customers.
https://www.notebookcheck.net/AT-T-rolls-out-5G-for-real-to-its-first-10-US-cities.447263.0.html
IIRC sub-6 in the US avoids the LTE bands because 5G will not replace 4G in the short term, while a smart move, especially to consumers, the "very-sub-6" 5G operating on previous GSM frequencies should have a very hard time surpassing typical LTE speeds operating on much higher frequencies, unless there was severe throttling of LTE in the US to begin with. I know the US network has mediocre density, but I don't know about actual speeds.