Any suggestions for prolonged out of instructional control ODD type behaviors?

Hello!

Our 16-year-old son has gone one week now, being out of instructional control and extremely defiant, oppositional and aggressive with profanities and insults towards me (dad).

The weekend before last, I felt we had made some progress because he accepted chores, twice, accepted a 24 hour consequence and I actually felt that we were able to bond while I was giving him the instructions on chores around the house.

Unfortunately, Sunday before going to bed we had a discussion because he did not want to relinquish his phone as we had agreed earlier, when I was going to bed. He promised to bring it and leave it charging in my room, when his downtime started, like his siblings do. I knew that this would be something he might fail to do, so I very clearly reminded him that if he did not bring it, he would be choosing a negative consequence. He agreed and said he would bring it, so I said OK.

He failed to bring it so the next morning, I asked him for his phone, which was intended to be a small consequence of loss of phone for the car ride and for a couple of hours after school. He fell out of instructional control and reverted to insulting and using profanities. Later that day, he continued the behavior and has continued since then for seven days now and said that he would never do another chore again, and never follow any instructions again.

To be honest, I stopped checking in with him to see if he was ready, because he was so dug in that I thought he would simply continue the behavior and I didn’t see the point. I’ve just had a conversation with him after reflecting, and I tried my best to let him understand that I was going to go back to checking in on him to be consistent, and to make sure that he didn’t think I was doing this to annoy him, or bother him but just to give him an opportunity to correct course. I also tried praising him for his having done the chores originally and let him know that I was proud of him, but this doesn’t seem to have gotten through to him as he remains angry and verbally aggressive.

I did a sodas exercise myself, trying to figure out what I should do here, which is how I decided to go back to checking in on him more consistently, but was wondering if you had any additional feedback or thoughts (or modifying if at all the rule of three, etc.), when dealing with an extreme ODD type Child who seems willing to go for extended periods of power struggling.
Thank you!