Probably the big Outlander has a lower aero drag coefficient, and I guess DI can get some more efficiency at lower rpms than regular FI. I assume the little Sport has mostly 2000's KISS car tech and less or no thought to under car aero and grill shutters, etc.
If you are mostly doing hwy then probably the big one is going to get the same mileage in your use.
At 60mph+ I find our 2018 Outback starts to get better mileage than my Focus wagon, which seems crazy when you look at them. But one is a KISS design from the 90's and turns about 2500 rpm at 60, and the Outback turns about 1600rpm with a lot of engineering done for aero, so even with AWD and 1000lb heavier, it uses less fuel as the speeds rise, even if the OB is also FI.
If you are mostly doing hwy then probably the big one is going to get the same mileage in your use.
At 60mph+ I find our 2018 Outback starts to get better mileage than my Focus wagon, which seems crazy when you look at them. But one is a KISS design from the 90's and turns about 2500 rpm at 60, and the Outback turns about 1600rpm with a lot of engineering done for aero, so even with AWD and 1000lb heavier, it uses less fuel as the speeds rise, even if the OB is also FI.