Welcome to the forum
With 33" tires and 3.73 axle your actual ratio is 3.16.
3.16 is good for highway speeds, keeps RPMs lower, but you will be using more fuel to get going from a stop so 80% city driving is whats dropping the MPG average.
Changing to 4.10 with 33" would give you an actual 3.48 ratio
Changing to 4.56 with 33" would give you an actual 3.87 ratio
4.56 would be closest to stock ratio and expected MPG from 3.0l Ranger
And you have to change both axle ratios since it is a 4x4
But at 12" wide you will lose MPG from tire friction, high MPG vehicles have skinny tires for that reason, less friction = better MPG.
You also have a pickup so aerodynamics of the brick, and I assumed raised up by the 33" tires so no benefit from ground effect.
You might be able to pick up 3 MPG with gear change.
Truck will also feel "peppier" with the higher gear, more low end power