Kean barely touched the ball when he came on. There is probably a link between that and DCL not being great.
Said it for years now, our play in the final third is atrocious. Over hit crosses, balls to nobody, passes slightly behind the oncoming players run, shooting when they should pass, passing when they should shoot, nobody making space in the box etc etc.
DCL is a part of that problem, so is everybody else, even our better players like Digne, Richarlison, Coleman (depending on the mood...) are guilty of it.