Zaniolo was arguably the Italian talent of his generation, but you can't buy guys who have done their ACL. In modern history I can't think of many examples of players who didn't lose a dimension after tearing their ligaments, and Zaniolo has done it twice now. The knee injury he's back from is his second ACL. He tore his first one in 2020.
There's another one of those generational talents at Roma right now in El Shaarawy. He's having a good season by normal standards, but the kind of career he was destined to have was as one of the best forwards in Europe. He'll never get close to that level. I think the same will be true for Zaniolo. He'll tail off in the next few years, probably after another string of serious injuries.