Highest grossing is not a valid measure at all. If so, here is the best rapper of all time.
Marshall Bruce Mathers III, aka
Eminem, is widely known as the best-selling solo rapper of all time, according to Eminem Pro, after having sold 220 million albums throughout his career.
Think about this, horrible Age of Ultron made more money than Captain America Civil War and Black Panther. Even Iron Man 3 made more money than Captain America Civil War. Captain American The First Avenger is The lowest globally grossing MCU title other than Hulk. Does that mean it's the worst movie? He'll no. It was one of the best. Even Iron Man is near the bottom and it was clearly the best Iron Man of the series.
Box office dollars do not mean much at all.