Szczęsny is a very good GK, he makes lots of unbelievable saves and rarely makes mistakes. Defence is ok, De Ligt is worldclass, Demiral is also very good but just needs to stop his stupid mistakes. Danilo has been exceptional this season, only Cuadrado and Sandro look slow. Midfield is the problem, they need atleast 2 worldclass midfield players who can create chances.
Szczęsny is very good but not elite, all the top teams have a better goalkeeper, could say much better goalkeeper. De Ligt is injured often right? I also feel like he's on his way to becoming world class but not quite there, he is young and already very good of course. Demiral I've seen many people say he's good but has a mistake in him almost every game. So for CB's they have injury prone De Ligt and mistakes in Demiral. Chiellini and Bonucci are too old and basically retired already. They do have decent fullbacks though.