I can't offer any advice because I don't have any children of my own but the comment about other children not listening to her made me wonder if she is emulating you? (not the smacking kids in the face part tho lol)

Children look up to their parents and I've noticed during free play, I see children acting and saying things their parents would do or say in their career. Could she maybe feel like she gets to have a say because it's her house?

My oldest dck will often say what I say when the children are not listening to her and I have to remind her that I am the teacher and the other kids are not too be bossed around. She is the youngest but bosses her older brother (and parents) around so I think she thinks she can do that here too, which I don't allow.

Also, the whole "negative attention is better than no attention" could maybe apply? I'm not saying this applies to you as I don't know you but maybe some more one on one time would help decrease the bad behaviour which could be caused by jealousy of her mom's attention on the other children?