Beerus was holding back.Super Saiyan Rose > 2 Super saiyan blue users (one of which was holding his own with beerus) he solos everyone
buu did it in one day while zamasu is draging his feetZamasu is the first villiain in DBZ with a good goal.
-Frieza: His daddy told him he was the strongest in the universe. His daddy game him an army and told him to rule the universe. He's a spoiled brat.
-Androids: They're programmed to kill Goku.
-Cell: The machine told him he can become a perfect being. So he fights to become what the machine told him.
-Buu: He was created to destroy things. He enjoys destroying things.
-Zamasu: He dissaproves human behavior, and thinks the world would be better off without them. He wants to erradicate all of them to accomplish his goal of a world without violence.