You’re not crazy.

I’d also recommend you and SO stop talking to BM about it. You don’t need to discuss punishments with her, just do what needs to be done. Handle it between the two of you, and de-triangulate stat. Her opinion on discipline in your house is frankly moot, as is your opinion on discipline in her house. I would also recommend keeping these things between you and SO and not reach out to BM directly, leave that to the person that procreated with her.

If you are giving more to this kid than you are comfortable with, stop. I don’t give a penny to my stepkids outside of holiday and birthday gifts. And I don’t do any heavy-lifting for them around the house, that’s on their dad. I learned that pouting yourself into someone else’s moody teenage daughter only brings pain, tbh. Step-relations are just not the same as bios, and bio-kids are mean and ungrateful as well. Disengaging protects the whole family from getting emotional, as well as protecting you.