The disability team are totally seperate from child protection. Having dealt with them now for 18 months they have done nothing but help me and my ds. That's my experience and shared by lots of people we know. We get 5 hours respite a week plus a number of overnight respite nights a year.
You've described my son at that age. Totally non verbal, he'd pull lumps of my hair out, smashed my new tv, broke every set of blinds we ever had, put a hole in my door and destroyed the wall paper in my bathroom. Made noises constantly, would scream all the time, have awful meltdowns, smear his own faeces all over his room. It was an awful time. The key is communication and dealing with sensory needs. Easier said than done i know!
Don't give up on communication, there are so many things you can try. Pecs, podd, makaton, high tech acc such as proloquo2go, lamp words for life plus loads more.
Sensory play can be really helpful things like Orbeez, sand, water play, paint, shaving foam, gloop, coloured rice/noodles, fidget toys, swing, slide etc. You can get all types of chews, my ds loves to chew and will chew anything. He has a number of chews he can use and is directed to them so my furniture is now safe haha. A weighted blanket is really calming for him. A wobble cushion helps him to sit down for longer periods. You can also get weighted lap cushions, I've also seen weighted snakes that can be placed on your lap or over your shoulders.
We still have really bad days sometimes but things are much more manageable. I'm not sure if things have gotten better as he's got older or I've got better at managing his needs. Probably a mixture.