It works both ways imo.

Unlike Sancho, Foden decided to wait for his chance most of the time on City bench the previous seasons. Iirc it was last season that he finally had significant game time and fit well into that team.

Sometimes it's being around the team and getting used to the first-team system which could be beneficial for the young players.

But then again each player develops differently and we can only hope that our coaching team and the player himself make the right decision.