Just been doing some random searching:
The Conversation, Canada
Evidence suggests that less than 1% of transgender people who undergo gender-affirming surgery report regret. That proportion is even more striking when compared to the fact that 14.4% of the broader population reports regret after similar surgeries.
For example, studies have found that between 5% and 14% of all women who receive mastectomies to reduce the risk of developing breast cancer say they regretted doing so. However, less than 1% of transgender men who receive the same procedure report regret.
Oxford Academic: Oxford University Press
Survey included the question “Have you ever de-transitioned? In other words, have you ever gone back to living as your sex assigned at birth, at least for a while?” The survey found that 8% of respondents had detransitioned temporarily or permanently at some point and that the majority did so only temporarily.
Cleveland Clinic
Research consistently shows that people who choose gender affirmation surgery experience redu9ed gender incongruence and improved quality of life. Depending on the procedure, 94% to 100% of people report satisfaction with their surgery results.