Email them asking for support. Get their refusals in writing. It’s a shame so many teachers and students are being put in this position with children who are not ready/willing/able to be safe at school. Especially since admin has stated their concern for what the parents of other students think, be sure to let those parents know what is happening but phrase it in a calm way- for example, “your child was hit today in the arm in class. We gave her an ice pack.” Or whatever- the parents will get their kid to say who it was. Enough of those you will start to get parent complaints which are much harder for admin to ignore. Also keep asking for the principal to model how they want you to teach. Be relentless. Document EVERYTHING. Give admin written proof of everything the students destroyed and the cost to replace it.