Мbappe is a generation talent, but even he hasen't developed so much since his 19eens. Gavi suffered a heavy injury, which is most probably due to playing so many at so high intensity, so early. There is also Asnu Fati, who broke early but he also suffers injuries. Garnacho is not a completed footballer, and he could finish like Rashforrd or Matrial - not fullfiling their potential because of being thrown so early in a high demanding environment. When one starts playing regularly young player , one puts a lot of pressure on that players do not make mistakes. Young players actually need to make mistakes in order to learn and grow up. The other issue is that if one pushes playing young talents with not fully developed bodies in the heavy circle 3 games per week, there is risk of serious injuries at some point.
If Carboni shows that he is a generation talent in serie B or even at Monza now, I don't mind to get him at Inter and integrate him as rotational player at the beginning, but he hasn't showed those qualities so far. And for me is useless to slow down his development, treating him like Asllani for instance.