OP, the mistake some step parents making is thinking by spoiling the children they will love them.
The truth is it doesn't change them.
They are either open to a relationship with you or not.
It can grow with time, but often it remains cool and distant no matter how much you try.
I have several friends that are step parents and I really wouldn't wish it on anyone.
They are nice kind woman but whilst the relationships don't have drama at all, it remains a really thankless job, largely due to the men they married.
One has a step daughter who never bothered with her at all, despite efforts for years, until she realised my friends retirement from nursing was perfect timing with her returning to work from mat leave. Suddenly she was calling her Nanny Hillary 🙄.
That stopped very quickly when she knocked it completely on the head with her step daughter and husband, and said childcare would be zero part of her retirement.
She didn't have sny children herself and certainly has no intention of being tied to providing free childcare.
My other friend has a boy the same age as my eldest, 25, she just had one child.
Her two step children have never bothered with her or him, again despite her best efforts.
Despite her efforts they prefer their mothers family on all occasions, whichbthey grew to accept.
She came into a huge surprise inheritance from her single godmother, a life changing amount, that she never in her dreams expected, last year.
Despite her telling her husband she didn't intend to share the news, he told his two daughters.
They are in their late 30's and when they suddenly started visiting and being very friendly towards her, she knew immediately that he had told them.
She refused to discuss it in any manner and told her husband every bit of it will be going to her son.
She is not sharing a penny.
She has been kind, generous and welcoming for 30 years to his children, and will continue to be, but they are not getting anything from this inheritance.
They are very hurt at not sharing it and seriously feel entitled to a third each apparently.
Things are now very strained in the family.
He chose to break her trust, cause huge upset about something that was her private business.
She is rethinking the marriage at this point.
This inheritance will set her son up for a very comfortable life on top of his professional career, when he inherits.
She feels under zero obligation to share this inheritance having shared everything 50/50 with him for 30 years.
She never begrudged helping fund his children, thankless though it was, but it definitely doesn't extend to her inheritance from her godmother.
Don't be used OP, save for your child and their future needs.