Who can I contact about an out of control child above my district manager? (preschool teacher)

I have been dealing with this particular child (and his twin brother who is also hard, but a little easier) since June and have received very little support from management, including at the district level, despite doing everything in my power to get help. For some context I teach a Preschool class (3 year olds) and this particular child has wreaked havoc since the day he turned 3 in June. He and his brother will climb and jump off of all the furniture, climb the fences outside, and throw hard toys across the classroom and at people. He punches, slaps, and tackles kids to the ground, often unprovoked, all day long. I have been unable to keep any fun props in my classroom over the last year because he will destroy them immediately, which feels so unfair to my other kids. He spits at kids, hits them when they’re already crying, breaks their things just to see them mad, and encourages other kids to do unsafe things like jumping off the shelves. I have kids telling their parents they are scared to come to school because of him, and a lot of them don’t feel safe in my classroom because of him. Telling them to stay away from him doesn’t work because he will throw hard toys from across the room and hit people.

I have tried absolutely everything I can think of, but I haven’t received much support. His behavior would get him kicked out of other centers, but my manger won’t even call home about it. I’ve tried every conscious discipline message under the sun. I’m redirecting constantly and getting nothing. His mom is very permissive with him and his brother and basically brushes me off when I bring up my concerns. I’ve taken tons of documentation that my managers do nothing with. They always say they’re trying to get ahold of a behavior specialist, but it’s been months and I’ve gotten nothing. I’ve tried contacting district, but they always just say ‘sorry, have you tried redirecting him to safer options?’ No one seems to realize how draining this has been for me. I am so burnt out and keep wanting to quit, but I care too much about my kids to leave. It’s only going to get worse if I quit on them, and I care about this particular child too, because if his behavior isn’t resolved by the time he goes to kindergarten, it’s going to be a nightmare. Since I’m getting no help, I’m trying to see who else I can reach out to, what else I can do. It’s been almost a year of dealing with him and I feel like nothing has changed.