I had a 2005 f350 6.0l.
I have a 2016 f250 6.2l w/tow package.
I towed with both, a 36ft 5th wheel 11+k lbs.
I have no issues towing with the 6.2l. Flat land tow is 9 MPG. Hills Mnts will down shift to 2nd gear and can maintain 60 MPH.
For the overall operation cost, the 6.2l is a bargain.