Good point about the quality and construction of the tire making the biggest difference.
I have ridden quality tires (gator skin or equivelant) from 23 to 32 mm. Personally on a commute I can’t tell the difference between the speed of a 23, 25, or 28mm tire. When Racing, I can but that is mostly about the sprint.
32mm is starting to be a bit slower for me. 28mm is the sweet spot.

FYI, on a mountain bike knobby, I ride about 17mph. on a road bike (that I normally commute on) I ride about 20-21mph.

However, at slower speeds, (say 15mph), a bigger tire will have less rolling resistance (basically less deformation, and follows the road contors better) and actually be faster at speed (although because of weight, slower to accelerate). When riding at 15mph or slower, I’ll take the bigger tire. At those speeds, the lower rolling resistance are more important than the weight and aero advantages of a big tire.