Look, your biological kids didn't ask to be brought into the world. You did that, usually for as purely selfish reasons as exist among people.
Adopted and step kids are a slightly different deal, but once you've made the decision to be a parent to them, then it's the same deal, again.
You owe them your best effort. All they owe you is the respect you've earned ... if any. If they love you, on top of that, be grateful.