If I compare his performance at Bayern Munich like the previous season, I think it's a little different and for next season it's still not certain that Lewandowski can be as productive as this season considering he's getting older.
If Barcelona gets the right midfielders and wingers then Lewandoski will score more goals next season. We saw that his form dipped after the world cup. It was after the world cup that players like Pedri and Dembele got injured. These two players are the two best creators Barcelona has so it affected Lewandoski.
If the news of Barcelona wanting to get Messi back is true and if they actually get Messi back, Lewandowski is going to be the biggest winner on the field because he would core a lot of goals through Messi. As Messi gets older he seems to be becoming more of a creator than a goal scorer. He still scores goals, but he creates more. With Lewandoski up front, Messi would create a lot of chances for him.