I have no idea what to do.

My son is turning into the most defiant and rude child I have ever met. I feel like I’m failing as a mother and have no idea what to do. We’ve tried time outs and then explaining why he went to time out. We’ve tried breathing techniques for when he gets upset. We’ve tried giving him a cool out time in his room. I’m running out of ideas. He gets out of his bed at odd times in the night playing and when we go in there and tell him to go back to sleep he laughs at us and gets out as soon as we leave the room. He refuses to nap and has hour long temper tantrums until we cave him and get him out of his room. He attacks his baby sister constantly and has even resorted to biting us when he’s upset. He doesn’t listen to the word no and refuses to listen to anyone about anything. I’m exhausted and embarrassed. Please help me.