Your prayer reflects a sincere desire to see God bring conviction, clarity and true restoration, and that desire is right before Him. It is good that you continue to bring this before the Lord with persistence, trusting that He who began a good work is able to complete it, and that His kindness is meant to lead to repentance.
Scripture shows that God often hedges a path with thorns, as in Hosea, not to harm but to block the way toward destructive lovers and sin so that a person cannot overtake what is harming them and may come to their senses. That coming to senses is pictured in the prodigal who, in Luke 15, recognized he had sinned against heaven and before others, humbled himself and was willing to take the lowest place. That picture helps us understand what real repentance looks like.
There is an important distinction the Bible makes between sorrow and repentance. Godly sorrow works repentance, and repentance always means a change. Worldly sorrow may express regret but it brings death and does not change the direction of life. Many can say they are sorry, but true repentance turns from sin, hates evil as Proverbs teaches, and walks in a new way. That is the change we should pray for, a repentance unto life that is demonstrated over time, not only in words but in a transformed life and in a willingness to walk in holiness.
You have asked for the church and family to be involved according to Matthew 18. That pattern is given for restoration. The first thought when a brother or sister is in sin should always be restoration, going gently and firmly to seek to bring them back. If they will not listen, others are brought in, and the church speaks, so that the seriousness of sin is understood and the person may be recovered from the snare of the devil. When that discipline is done, it must be done with gentleness and humility, keeping an eye on ourselves lest we also be tempted, as Galatians 6 teaches, and with the aim that the person would flee youthful lusts and pursue righteousness, faith, love and peace with those who call on the Lord out of a pure heart. It should be firm because sin is dangerous, but also gentle so that the door to return remains open, like the father who had compassion when the prodigal returned.
It is also wise to pray as you have that she would avoid those who have a form of godliness but deny its power, and that she would be surrounded by those who will speak the truth in love. The Word of God is the sword of the Spirit and it is living and powerful to convict of sin, of righteousness and of judgment as Jesus promised the Holy Spirit would do. We can ask God to raise up faithful messengers who will not fear man, for the fear of man is a snare, but who will fear God and tremble at His Word.
We do not look to the history of the church as our model, for that history is often marked by failure and lack of love, and the Lord Himself warned churches that without love and without repentance His presence would not remain. To five of the seven churches in Revelation He called for repentance. Our model is found in the book of Acts, where the church sought to walk in the power and purity of the Spirit. Part of that purity involves putting out leaven and dealing honestly with sin, not to condemn but to see power and health restored. God always preserves a faithful witness even in difficult times, and He calls His people back to Himself.
We agree with you in asking God for inner healing and clarity, that the wounds described in Isaiah would be tended by the Shepherd of Psalm 23, that knowledge of God would grow, for the fear of the Lord is the beginning of wisdom, and that she would come to hate evil and love what is good. We also agree that any future relationship must be on the foundation of faith in Christ alone and the biblical pattern of marriage as a lifelong covenant of one man and one woman, with purity kept within that covenant. We cannot ask God to bless what His Word calls sin, including being unequally yoked or walking in a divided vision where two cannot walk together except they be agreed. Instead we ask God to make holy and clean according to His Word, which is fully inspired and profitable.
God is not willing that any should perish but that all should come to repentance, and yet Scripture is clear there is wrath and distress for every soul that continues in evil. His patience is not approval, it is mercy giving space to turn. Continue to pray that God would warn, convict and draw her and those around her, that pastors and family and friends would act not negligently but with love, reverence for God and zeal for His covenant, completing what they have said they would do in love.
We will join you in praying that God grants repentance, that she escapes the snare of the enemy, that others also learn to fear sinning, and that if God grants true repentance and new birth, there will be fruit that demonstrates a changed heart and a willingness to walk in step with the Lord and His calling. May the Lord give you patience like His own, steady hope for the future He promises to those who turn to Him, and wisdom to love firmly and gently as you wait on Him.