How do you know? How can you be certain? Isn’t overconfidence the best way to get beat by a lesser opponent? Resting starters sure would signal to a team that the opponent doesn’t need to be taken seriously. Why does every other coach in the country start virtually every game with their legit starters? What you’re proposing would be a radical shift from what virtually all coaches everywhere do. Has it occurred to you that they might have good reasons for doing what they do? Do you understand what hindsight bias is?