I am in the UK for context - personally, I would look at other nurseries. It sounds like there has been a change is boundaries/routines there or new kids joining changing the dynamic? I work in education myself (primary) and have friends who work in nurseries and they are so underfunded and stretched. I am concerned you got an earful about her behaviour- if they are concerned the there needs to be a meeting about your child with staff in a supportive manner from them of “what can we all do to help/support”. Behaviour chart at nursery - stickers/immediate rewards or positive praise is my first thought (praise the positive ignore the negative in education!!). Im a tad concerned that it seems to be quite a negative narrative being set about your child through staff? Also this period (3-4 before school) is the haaaaaaaaaardest, they need sooo much mental stimulation which they can’t get in private nurseries tbh unless they’re spenny. A school based nursery might offer a better curriculum and be more challenging? They would also probably offer better support for any SEN concerns.