I agree that none of Dame, CJ or Stauskas are great defenders but they don't have the same faults. CJ is a decent help defender, he rotates, he comes to help, he's active, he's below average as one on one defender but I'd say he isn't better or worse than mediocre as a defender.
Stauskas is weak but he isn't a liability, the 2nd unit plays very good defense.
Dame as I said is simply clueless as a help/team defender and mediocre as one on one defender. This is why I think the paradigm shift should be to not hide him on their weakest guard, making him absolutely useless as he doesn't help defend, but have him on the ball like when he was matched with VanVleet. He did a decent job and his steal on VanVleet in the fastbreak actually gave us the win