What is the belief or feeling that has made return feel impossible or impractical? Is it based on what the Qur'an actually says — or on what you have assumed it says?
Sit with the idea that the door does not close. Does that feel true to you right now? If not, what makes it difficult to accept?
What does sincere turning actually require of you — not performance, not ceremony, but genuine intention? What would that look like, practically, today?
Are you seeking forgiveness, or are you seeking certainty that you are forgiven? These are different things. The Qur'an speaks to the first more than the second.
What would beginning again look like in practice, even in a very small way — not a transformation, but a single honest step?