Use this summer as an opportunity to build a new Italian core. Rotation of the roster during the season would be minimal, since there will be less games.
I would be thrilled going into the season with this (not necessarily as the presumed starters every game):
Donnarumma
X-Gabbia-X-Cambiaso
Ricci-Rovella-X
Orsolini-X-X
Next summer they can go after Calafiori and Tonali, hopefully with the pull of being back in the Champions League.
To complement the Italian core they would have the prospects of Camarda, Bartesaghi, Zeroli, Liberali. Add Leoni to that group.
I’m not saying that Milan will be successful in the CL with these players as starters, but that could be the group the carries the culture, the continuity and the passion that’s been lacking for many years. Players who are also bound to permanent fixtures in the Italian national team for years to come.
I think that the only time they should look abroad is when they have a chance to add either Star players that elevates the starting-11, or wonderkids bound to reach stardom.