“step” daughter

i love my “step” daughter and my fiancé so much but she is SO loud because her mom lets her do what she wants and scream and jump as much as she wants whenever she wants. it’s become a really bad habit so when she’s here w me and her dad we try to keep her as quiet as possible as we’re in an apartment w neighbors and we’re upstairs. not saying like she has to whisper but a normal talk and a laugh and all that. no need to scream bloody murder or jump over and over again. my fiancé is also very... um not with it? as a dad i guess, the mother of his child just let his daughter back in his life after a huge legal battle so he’s not really sure what to do with her and all that.. but its to the point where i’m literally the one cooking for her and bathing her and doing her hair and changing her clothes and giving her her medicine and making sure she pees and trying to keep her calm and quiet and busy while her dad just plays video games to try to keep himself awake as he works nights. she’s here to see her dad and i feel like shes only “seeing” me. i don’t mind having her here at all but i just feel like i shouldn’t have to do every single thing when she’s not even my child. i just don’t know what to do guys. i hope he’s not like this when our new baby comes.