Tallying Up Dom L at the Athletic's rating system, this is how he ranks the defensemen through the three games. This is only one rating system, so take it for what it's worth, but I decided to seek out more data after the discussion above.
Werenski: .98, -.03, .52=1.47
Sanderson: .32 (only played Sweden game)=.32
McAvoy: .63, -.40 (didn't play Sweden game)=.23
Hanifin: .01, .03, .17=.21
Fox: .34, .08, -.27=.15
Faber: .21, .26, -.36= .11
Slavin: .34, .09, -.56=-.13
Takeaways:
Werenski has had two great games and one break even game.
Sanderson did well in his only game.
McAvoy had a good game and then a bad game, but generally more good than bad in only two games. Hanifin has basically slightly broke even in every game.
Fox has slightly more than broke even with a good and a bad game thrown in, yet relatively close to even in each game.
Faber is pretty much the same as Fox, but his best game a little worse and worst game a little worse. Slavin had two solid games, and then struggled against Sweden. Not terribly underwater, but slightly.