Always remember, you're the boss. You have all the power. There is NEVER a need for a power struggle with your kid. That is what he's trying to do: get into a power struggle with you. Just laugh and say, "Nice try, buddy. I'm the boss. You are not. Wanna push it? If you chose to do so xyz will happen".
xyz should be something he really, really cares about that is not abusive or denying affection, if that makes sense?
For my kid, all I need to do is say, "Five days, no video games if you keep that up" and he immediately stops whatever he is doing that is wrong. Find that thing with your kid and you have all you need.
Kids constantly try and get into a power struggle with parents. Don't engage. If they need to try and argue you, feel free to listen to their argument. Repeat it back to them. Ask them if you understand what they are trying to say. Once they affirm that, yes, you understand their position say, "Ok. I get what you're saying. Nevertheless, I stand by my earlier decision."
My child runs screaming now when he hears "nevertheless". He knows I won't budge. The three older kids I helped raise also still hate that word. The oldest is 25 and will cringe when she hears it, lol.