Not as good as I did with my 19' Classic HEMI with 3.21 gears
I just bought a new 2023 Classic Warlock with the 3.92's a few weeks ago.
Love the 4th Gens, and while I do notice more fuel consumption, it's not too bad.
At 120KM/H with 3.21's I was at about 1400/1500 rpm's
At 120KM/H with 3.92's I am at about 2000 rpm's
Also, with new engines, they require 5,000 to 6,000 miles to really break in well and settle in before you'll see its optimal fuel economy capabilities.
However, how you drive it also greatly affects your consumption as the 3.92's like to jump off the line like a jack rabbit with a heavier foot.
I'd also recommend a good synthetic oil when you start changing it, and quality fuel, too.
These things also help with efficiency and with longevity of your HEMI as well.