Skinny light wheels are better than heavy fat wheels and tires.
Weight that you move up and down (legs, shoes) pedaling is worse than weight that just sits on the bike. If you are standing to pedal, then a backpack could be worse than the same weight on a bike rack or the bike itself.
Heavy has an advantage going downhill. Light has an advantage climbing.
At higher speeds or in wind consider drag and aerodynamics. A big profile is slower than a small profile.
All of these assume other factors are equal. Fitness, power.