Also, I feel very strongly about this because I did go through a VERY significant Christian phase of denial, where I tried to pray away my trans desires. For about 5 years, I was a "success" story. I renounced my trans desires, prayed to be cured of them, and for years reported that I was now over it, that God had cured me. And this is what any survey of "ex-gay" therapy measures... the immediate post-therapy outcome, in which most people will indeed believe themselves cured, and feel like their lives are headed in a different direction, and report themselves to be successes. The sheer act of admitting that they have these desires at all, and laying them before God, is a HUGE mental relief when you do it for the first time. So it's easy to believe that you really are cured.
The thing is, though, it doesn't last. I believed myself cured, and yet all I was doing was basically denying that the thoughts even existed when they came back. Instead of feeling the dysphoria, I actively repressed it every time it came up. Every time gender-dysphoric thoughts hit my mind, I'd pray to God to take the desire away from me, to "take the temptation of the devil out of my head"... EVERY single time it came back up, for 5+ years. In the short term it helps you cope. But over the long term, it starts building resentment. You start to hate yourself for it. You start to get upset, asking God "why, why am I still having these thoughts? Why can't I just be freed from this? Why can't I be a good Christian like everyone else?" And yet time and time and time again, no matter how much you pray, it always keeps coming back. And the exhaustion at fighting it all the time grows, and the self-hatred for not succeeding in getting over it grows. It eats you alive after time. You feel like a failure, and feel like you're living a lie. You become anxious and socially isolated because you're so ashamed of yourself. And the only question becomes whether you embrace your "sinful" imperfect self, or whether you keep fighting it and denying it to your own destruction.