You'll like the 3.92s, I do in my '17. I usually average 17.5-18mpg unloaded and I certainly appreciate the extra towing capacity. You may want to invest in some helper bags though, I plan to on mine. I hooked up our 28' box trailer at work just to move it around the building and it squatted my truck all the way to the stops unloaded, which is ~5k unloaded
I've had 3.92s on my 2001, 2005, and 2014. I have air suspension on the 2014 and it's standard on the 2023 Limited. No squatting at all (the trailer is the ONLY reason I got those again). My trailer is 6K loaded (max rated for 7000).
I would rather have a setup like the 2500 - regular springs with rear helper bags (factory). The auto-leveling feature of the 4-corner air suspension is nice.
The 33 gallon tank is nice... I have that on my 14 as well. When the light comes on, you still have 7+ gallons left LOL (can usually only get 25 gallons or so in it).
Hope I don't miss the 6'4" bed - they couldn't order that anymore for 2023 (it came standard with 33 gallon tank). It's a real b1t@h to park.
I get 14 mpg with my truck now (I drive 3 miles to work). I'll rarely see anything above 17 on the interstate, but I68 is probably the most mountainous interstate in the East (2000-3000 feet in elevation). You're always going up or down. Ford engineers come here from Detroit to test F150 & F250 transmission calibrations because of the long, relatively steep grades. Nothing get's good mpg's here.