I've read your earlier threads. I get the impression that you're very unhappy with your SD right now. IIRC you've even spoken of removing her from your wedding party.
If you treat her badly, and focus on what she's doing at her mom's house (which is frankly none of your business and something you can't control) OF COURSE she will want nothing to do with you!
You're not married yet. Your partner's job is to look after his children. Your happiness has to come after that. TBH, I kind of get the impression you came at this the wrong way. I get the impression that you tried to make his kids like you, and when they didn't do what you wanted, you got upset.
These relationships have to grow organically. You don't know what SD is whispering about to your OH. I know that my DSD tells her dad things she doesn't tell me. She likes to go on drives with him, sometimes just the two of them. My response is to not worry about it. What they discuss isn't my business.
SD doesn't have to like you. If she's answering when spoken to she's generally being respectful. If she leaves when you enter a room, don't push it. You need to give her some space. Eventually, when she's ready, she will come to you.
I get the impression that you're not overly thrilled with having to share your OH with his kids. Guess what? He had those kids before you got together. Until you marry, they are going to be his top priority. If you're not ready to accept that, you may need to find a new partner.
For the record: I am a proud stepmum to a lovely 13-year-old girl. Hubby and I met when she was 5 and married 18 months later. She and I have always had a great relationship. I don't push or smother but just try to be there for her, which I know she appreciates. Sadly she and her mum don't get on the greatest (more down to her mum I think than her, knowing how her mum is and how DSD is with us). She proudly tells people that she has two mums. I am very fortunate to be her mum and I don't take it for granted that we get on well.