@scottwilson It sounds like you're dealing with some sort of oppositional defiance disorder.
My oldest has it and it's a nightmare. I can't point to anything that was 'successful.' He's out of the house now but he's incredibly difficult to even get along with.
It's exceedingly challenging because it almost doesn't matter what you do or try, nothing worked for us. I could leave him alone and he would completely fail and didn't care. If I tried to engage with him on his school work and it's status it would become a literal violent fight (he would get violent, I called the cops multiple times, once he called the cops on me and they pulled him outside to tell him how wrong he was). When he moved out, all he does it contact me when he needs money or something like that.
I'd cut his phone and figure out how to lock him out of your space in the house. I literally had to create a safe space in my house for me and my other child away from the oldest. When he moved out the freedom we experienced from the torment of this child was incredible. I will never let him in my home again. It's not easy to be in a situation like this. You love your kid but they get completely deranged and there isn't anything you can do about it.
I've always been told that firm boundaries are needed. I would want to cut the phone off completely or at LEAST but further limitations on his phone saying that the more he acts out the worse those things are going to get. Compliance with your house rules will lead to fewer restrictions. Period. Lock yourself away and if he starts banging on your door 'to annoy' you or does any property damage, call the cops for help because your options are literally few.
Edit: I see you're dealing with some of the same things I've been dealing with regard to self harm and violence. I don't have any solutions but I can tell you that you're not alone.