IDK...
I never really thought of Brad as a "great actor"
I think that the notion of "great acting" is hilarious and way too many awards, honors, fanfare are placed on actors to begin with. Either you can believably play the part or not. If not then you're a bad actor and bad acting is obvious.
Some actors can draw you into the movie a little bit more than others. Philip Seymour Hoffman was a great actor who could play many different roles and add charisma to each one.
I think Brad Pitt has had great roles. The roles he had were so good even an average actor would have looked good performing them.
I did like Once Upon a Time in Hollywood and actually thought he acted really well in it.