Jothar, Dumbledore Z”L was only involved in Toeiva as a 17-year-old youth. The rest of his life he lived as a tzadik, he was very sorry about his past which is why he was afraid to confront Grindelwald until the magical community pretty much forced him to, at which point he atoned for his past by defeating Grindelwald and saving the world from that Toeiva. Dumbledore was the ultimate Ba’al T’shuva although his guilt never allowed him to marry normally and kept him from saving people earlier. Grindelwald himself also did t’shuva before being killed by Voldemort many years later.
I have heard theories that the reason Dumbledore was at the “train station” with Harry at the end of Deathly Hallows was because he was not yet allowed into Olam Habba, he was stuck in the middle as a kapara.