I'm confused with your post.
Because you seem to come to the conclusion that a good manager/head coach is important, but only when it suits you (E.g. Winks, Ricardo, Daka, Mavididi)...But that Faes and Vestergaard are just bad.
I could write a hell of a lot about this, I speak often to the two guys next to me at the game about how under Enzo we were basically able to give the ball to Fatawu and Mavididi on the touchline every game, often, despite other teams knowing we were going to do it, this is because we were well coached and had good patterns of play.
But I disagree that Mavididi was particularly effective, I thought Fatawu was, he would take his man on for fun game after game. But I was constantly disappointed with Mavididi, especially because he had KDH to combine with that side. Mavididi was given far more freedom by the fact Fatawu/KDH/Vardy were such threats. Mavidi fools a lot of fans by looking like he's a threat, but all he does when he gets the ball to feet is a couple of stepovers, drops his shoulder as though he's looking to be direct....Then pass it backwards. His decision making is poor.
Winks is a terrific footballer, still the best central midfielder in this league imo.
Ricardo's legs went years ago, Maresca helped him a lot with the different role and he had KDH/Ndidi doing his running, which is true for Winks too.
We were much better coached under Enzo. But even so, if you watch us play today, you can still see that Vestergaard has that progressive passing ability which is superior to anyone else in the squad.