The phrase "main benefactors" refers to people or groups who provide the most help, support, or financial assistance to a cause, project, or individual. They are the primary or most important contributors. Full definition
China is North Korea's main benefactor, providing most of its food and fuel. (fortune.com)
In their defence, they didn't get much help or protection from the midfield as Liverpool continuously attacked them down the right flank, and Sadio Mane in particular was the main benefactor of it all as he bagged a brace and in truth should have had more. (caughtoffside.com)
Christian Eriksen was naturally the main benefactor of this, but Dele Alli equally enjoyed space to roam. (spursfanatic.com)