I'd say Usyk, good defence, good offence, solid power, good chin, can fight on the back foot but can also press and break down a fighter if needed. Canelo for me while exceptional in so many ways still has a weakness against good movers as shown recently in the BJS fight.
Crawford IMO. Good power, speed, high ring IQ, a switch hitter, good body puncher, solid defense and footwork, great counterpuncher and he's effective on both the front and back foot.
Usyk. While Canelo got mainly 2 big weaknesses - stamina and foot speed. I see only one small weakness in Usyk - power, and even that is debatable, since he is a bit small for HW and the CW's he couldnt KO, were fighters with 0 losses like Briedis, Gassiev, Hunter or fighters with good chins.
I'll go with Alvarez. Obviously, he has a very good offense. His defense, like Roberto Duran's, is subtlely good. He uses distance and head movement to great effect.
Canelo. He does have some weakness, but to me if he was still a WW, he’d beat both Spence and Crawford.