I have a slightly different idea, Haaland is not the key factor that helped Man City win the championship. Erling Haaland is a small player in a big match, he always fails in the final.
Manchester City won the EPL title because Erling Haaland made good use of his goal scoring opportunities and also his teammates played a major role in game victories. Pep Guardiola arrange his strategy and every player played a role in accomplishing their targets, no one was left out. Erling Haaland is a top player and goal machine for Manchester City.