As long as you fear the Lord and sought Him with all your heart, soul, and strength, there is no sin that will not be forgiven.
I have written quite a bit about the sanctity of the body and how eternity is the solidification of one’s consciousness. Based on the understanding of sin and how detrimental repeated sins (caused by the hardening of hearts) can be, will God forgive sins that were sealed by the unreversible effects of plastic surgery?
As they traveled along the road, they came to some water and the eunuch said, “Look, here is water. Why shouldn’t I be baptized?” (Some manuscripts do not contain this verse: Philip said, “If you believe with all your heart, you may.” The eunuch answered, “I believe that Jesus Christ is the Son of God.”) And he gave orders to stop the chariot. Then both Philip and the eunuch went down into the water and Philip baptized him. When they came up out of the water, the Spirit of the Lord suddenly took Philip away, and the eunuch did not see him again, but went on his way rejoicing.
— Acts 8:36-39, NIV.
A little background before we begin.
The eunuch in the passage was a court official serving in the royal treasury of Candace, queen of the Ethiopians . This suggests that he was not gay. He was a willing eunuch. His official status meant that he should be an actual eunuch and not a person who has sworn into celibacy. The fact that he was on the way back from Jerusalem after worshipping  and was reading the book of Isaiah  showed that he must have feared God and must have been from a high status so as to be able to get a copy of the scriptures.
Given this background, we can infer that it pleases the Holy Spirit to indwell in people who feared the Lord and is genuinely seeking God, despite his / her physical background (and in context, a eunuch who should have been excluded from the assembly of God ).
After putting his faith in God, can the eunuch, by his personal will, be restored to be a complete man again? Definitely not. Unless the power of the Holy Spirit works miracles in his life, he will remain a eunuch. But unlike the Old Testament, he can now be grafted into the family of God in the time of grace.
What has this got to do with a Repentant Transgender?
Like the transgender, both the eunuch and the transgender both had their sexual reproduction organs removed or destroyed by means of surgical procedures. But unlike the eunuch, the transgender had been indulging in unnatural sexual relations. Now, assuming that this transgender is repentant, convicted of sin, and is desperately seeking the Lord for forgiveness, the Lord is merciful and will draw Himself close to the transgender.
Like the eunuch, the transgender will not be restored to who he/she once was, unless a miracle happens. But the truth still stands — God will forgive the repentant transgender of the sins committed, no matter how severe the sin may be .
But unlike the eunuch who can continue living his identity, the repentant must make the tough decision to return to his or her original identity. It isn’t about sexuality or preferences here. Anyone who has purposefully removed their sexual organs has chosen to abstain from sexual relations. Hence, the call to return to one’s own identity isn’t about sexual preferences or feelings. Rather, it is about not causing someone else to sin .
If the transgender is truly repentant, then this principle should be easily understood. I am not saying that the repentant transgender must go through reversal surgery (even though this is encouraged). Rather, I am saying that the repentant transgender should live and dress in accordance with their original identity so that no one else might be led astray and into sin.
Jesus straightened up and asked her, “Woman, where are they? Has no one condemned you?”
“No one sir,” she said.
“Then neither do I condemn you,” Jesus declared. “Go now and leave your life of sin.” — John 8:10-11, NIV.
Leave your life of sin.
You’re now free from the bondage of sin. Not only so, but you are also free to return to the identity that Christ has predestined you to have before the universe began. It is only when we’ve found our identity, our purpose, and our calling in Christ, will we be able to experience true freedom. No more will earthly distractions like sexual appeals or the need for affection overwhelm our minds when God will personally satisfy our deepest desires.
But whatever was to my profit I now consider loss for the sake of Christ. What is more, I consider everything a loss compared to the surpassing greatness of knowing Christ Jesus my Lord, for whose sake I have lost all things. I consider them rubbish, that I may gain Christ. — Philippians 3:7-8, NIV.
After we have experienced the surpassing goodness of Christ and have tasted the unfathomable power of the Holy Spirit, all that we previously value, be it financial wealth, relationships, acceptance, and love, we count it loss. Because the kingdom of God is like a pearl hidden in the ground. A man who found it delightfully sold all that he has to buy the land. All that he had he counted as loss because of the surpassing profit he knew he’d made when he found the kingdom of God. Likewise, the value of our identity that was written before the foundations of the world surpasses all things that we have ever experienced in the physical world.
The old has gone and the new is here. Only do not fall back into sin or cause others to sin again.
 – So he started out, and on his way he met an Ethiopian eunuch, of Candace, queen of the Ethiopians. This man had gone to Jerusalem to worship. — Acts 8:27, NIV.
 – Then Philip ran up to the chariot and heard the man reading Isaiah the prophet. — Acts 8:30a, NIV.
 – No one who has been emasculated by crushing or cutting may enter the assembly of the Lord. — Deuteronomy 23:1, NIV.
 – And so I tell you, every sin and blasphemy will be forgiven men, but the blasphemy against the Spirit will not be forgiven. — Matthew 12:31, NIV.
 – But if anyone causes one of these little ones to sin, it would be better for him to have a large millstone hung around his neck and to be drowned in the depths of the sea. Woe to the world because of the things that cause people to sin! Such things must come, but woe to the man through whom they come! — Matthew 18:6-7, NIV.