Di Maria's quality and experience can help Juventus win the Scudetto again, but as you said, Di Maria cannot do it alone without the support of other players. After the midfield problems were resolved, Juventus also had to improve their defense and attack power. The main problem is that the Juventus defense is still very fragile, Juventus must move quickly to find a replacement for Chiellini who left Juventus at the end of last season.
There are several good defenders to choose from for Allegri next season such as Bonucci and Matthijs de Ligt, but the need for a central defender for the 2022/2023 season is still highly expected considering that Juventus quite often rely on 3 defenders for a 3-5-2 scheme. Rumors of Monaco defender Guillermo Maripán also sound good for Juventus, but they are yet to be confirmed.