I wouldn't be surprised if most of that difference in feel could be explained by frame rigidity rather than weight. I love my steel frame but I know it's not super efficient.
I've got two different sets of wheels for the same gravel bike. Its standard 42 mm wheels for gravel and 28 mm slick wheels I assembled for road. Same brake rotors and same gears on the back. The set of road wheels is about 1.5 kg lighter (3 pounds). The bicycle seems to fly with them. Rotational mass is really important and also slick vs threaded.