I have owned both,2021 cc4x4 7.3 w 3:55 and 2022 cc 4x4 6.7 w 3:55.I liked the 7.3 , but I tow my fifth wheel a lot .It had plenty of power as far as towing but when towing up a grade it would downshift to fifth gear and really roar to get up to speed.Normal driving it got about 14.5 mpg,and towing the fifth wheel about 7.5.
The 6.7 tows effortlessly.It doesn’t downshift unless it’s a pretty good grade, and is very quiet.The 6.7 gets about 19.5 with normal driving and I get about 12.8 mpg towing a 14000 lb fifth wheel.I like them both but for me I tow a lot and the 6.7 is hands down better for my use.