I have used this site as a resource for rolling resistance:
https://www.bicyclerollingresistance.com/
They have a great comparison between 23, 25 and 28mm in my favorite tire, Conti-GP4000.
https://www.bicyclerollingresistance...0s-ii-23-25-28
However, it is interesting to note that what is gained by going from a 23 to a 28 is soon lost when lowering the pressure from 100 to 80 or less. Lower pressure requires more effort / watts.
I also live in an area of rolling hills. If I am not climbing I am descending to some degree and I am also a believer in rotating mass / acceleration as a past drag racer. Weight added to the outside of a wheel when accelerating has a multiplicative effect on power needed versus weight anywhere else. When climbing the effort is akin to accelerating each pedal stroke. When descending, we could argue that the added weight adds the inertia (hence faster descents), but the differential does not equal out. Most recently I converted a commuter bike from 700x22 tubular to 700x32 Gravel King tires. Ride was so much smother, but the additional 100-200g per wheel slowed my 30 mile commute by roughly 1-2 mph. I will continue to do the fat tire thing on that bike, add fenders an make it a comfortable ride it anywhere bike, but that bike will not be taken when I want to be fast.