I'm not convinced that we're quite as bad as you paint it to be BC, though I will concede that there are quite a few players that won't make the cut with Ange.
The players have been forced to play negative Football under the last 3 managers, and we can see that it's affected them negatively. It's not their natural game, so any joy has been sucked out of them, with their self confidence sucked down with it.
Virtually every player we have either came from sides that didn't play that way, or were part of the Poch era where we went after the opposition from the get go.
I'd like to think that these players will find that joy again under Ange, and a kind of 'muscle memory' will kick in. They're not having to learn a different way of playing, as they've all played this way before. What I think will take time is the understanding between the players, knowing your team mates should be and trusting that they'll be there when they should be. They've played like strangers under Conte this season gone, which Conte blamed them for. Whilst he may be in part correct, you can't overlook the fact that our players really didn't look happy playing that way. So many lethargic starts to games said to me we had players enduring a game rather than revelling in it.
Positivity is severely underrated. Belief even moreso. Those 2 ingredients can make an average player good, and a good player excellent, especially if you provide them with a playing style that encourages that to flourish, and a meritocracy where you're awarded for your efforts, not your name or time served.
I think we have a core of talented players that will take to his brand of Football like a duck to water. The key will be getting them to trust each other and willing to run through walls for each other as much as him.