I have a 2019 Laramie Level 1 4x4 CC. There is no information on the Window Sticker for tank size. However, the build sheet shows 26 gallon tank. Maybe my dealership configured it with the 26 gallon; but there is no mention or upcharge on the Window sticker. I'm pretty sure it is 26 gallon because when the low fuel light came on it showed I had 50 miles left. At 16.5 MPG average for that tank; then it should have approximately 3 gallons of fuel (reserve) left for that 50 miles (as calculated by the truck's computer). When I filled up, it was just short of 23 gallons.
Insofar as tank size and driving; I have no issue with the fuel quantity of my truck. I don't drive a lot regularly, so I usually have to fill up every two weeks. On road trips I get somewhere between 400 and 450 miles per tank. I like to stop once every 3 or 4 hours on trips; so the gas has always made it to the next stop. I think the only downside to the smaller tank would be if you are towing long distances. I only tow my boat within a 200 mile maximum radius of home; so the towing mileage really isn't an issue for me.