There's only so much young players can improve without playing.
This is why, despite uncertainty about how good they can actually be, I'd have had Holgate, Davies, and Calvert-Lewin playing as many minutes as possible in the second half of this season. Those three rarely look out of place when called into action against senior pros. I think you need to invest minutes in young players like that, especially when you're not competing for anything. That's a big part of how you find the Kanes, Allis, and Rashfords of the world.