https://pickuptrucktalk.com/2024/03/2025-ram-1500-mpg-new-hurricane-wows-disappoints/
If you look at the (Grand) Wagoneer Owners Manual, It states the following:
3.0L STANDARD OUTPUT ENGINE
Do not use E-85 flex fuel or ethanol blends greater than
15% in this engine.
This engine is designed to meet all emissions
requirements, and provide satisfactory fuel
economy and performance, when using
high-quality unleaded regular gasoline having
an octane rating of 87, as specified by the
(R+M)/2 method.
The use of 91 or higher octane premium
gasoline will allow these engines to operate to optimal
performance.
EPA Page:
https://www.fueleconomy.gov/feg/PowerSearch.do?action=noform&path=1&year=2025&mclass=Pickup Trucks&srchtyp=marClassMpg&pageno=1&rowLimit=50
2025 RAM 1500 has the same SO engine. So the EPA economy figure happens in a sub-optimal state (i.e. retarded timing probably).