Uhh...people literally regret medical procedures all the time. Virtually every single medical procedure involves some potential amount of harm/risk.

So much in fact that there are literally research studies on it.

https://www.sciencedirect.com/science/article/pii/S0949265821003535

I'd venture to guess there are more people as a percentage that regret their knee/hip replacements than there are people that regret their transition.