That is really impressive for a 3-ton long-body SUV.My 2020 Suburban Premier has the 10 speed and the 6.2. I heartily recommend it.
It isn't getting 23 or more MPG on the highway but that could be because it only has 40k miles on it. I'm getting more like 22. It does get much better gas mileage than our 2017 Nissan Titan though.