Iron Man

Iron Man sacrificed himself to save the Earth when he wore the infinity gauntlet to terminate Thanos and his army. Iron Man and the rest of the Avengers knew that the infinity gauntlet is one of the most powerful objects in the universe and anyone who would wear it will likely suffer severe damages. However, Iron Man was desperate to save the Earth and his friends in Avengers Endgame. So, he wore the infinity gauntlet and snapped it. He is G.O.A.T.