Answer:
Hawkeye 100%
Step-by-step explanation:
If you think about it.
Avengers: Loki had him under mind control and was on Loki's side he won and then the mind control ended then he was on the Avengers side the Avengers won.
Avengers Age of Ultron: Avengers had Clint and they won every battle
Captain Civil War: Tony didn't have Clint and he lost whereas Steve had Clint and he won
Avengers Infinity War: Clint wasn't there, and they LOST
Avengers End Game: They had Clint and they won
Come on that says a lot. Tell me I wrong with these facts.