Robert Downey Jr is the obvious case of a person who had a redemption arc, to simplify it he was a promising actor that got addicted to drugs, fell off, went to rehab and then became a huge hollywood big stsr known, even known for being Iron Man.
What real life person had a redemption arc?
Jimmy Carter was always a nice guy, but a hapless president. His reputation improved substantially after he started doing work for Habitat for Humanity. He was no longer the guy chased by a swamp rabbit while out fishing; he was a humanitarian, doing his damnedest to serve the community.