Just as Hansi flick transformed Barcelona with the available players in his squad last season, I think Allegri can try also since he already have the Seria A experience, and he is a good manager overall.
Transformed....
Barcelona were winning La Liga even before, and they won it even easier in the 2022 edition before Flick, Milan is all over the place, before winning Serie A they spent 7 years not reaching the 4th place, and nowadays their game is simply chaos. Barcelona always had the players to win La Liga, they were always there, Milan even when winning it!
The only advantage Milan has and that makes a comeback somewhat a possibility and not straight fantasy material, is that the other teams suck just as much, there is simply no other team that can say for sure they are favorites and will not flop again like they used to, every single one of them.