That's got a 3.21 rear end. Are you comparing it to a similar one?
I realize that this is somewhat off topic for this thread, so I apologize in advance.
The automotive companies and EPA don't go to that level of granularity on the EPA estimates. On trucks (and most cars/SUVs), they typically only rate each engine, transmission, and drive (4x4 vs 4x2) combination. A lot of people get the 3.92 and complain that they can't hit the estimates for MPG. My 2019 is rated the same as the 2021. I have the 3.92 and have never seen anywhere near 22 highway, but I don't really care.
My comment was simply due to the fact that all of the engines, transmissions, and drive combinations are essentially carry-overs from the 2021, so how did they get an extra mile per gallon in the city? Seems odd.