We are glad that you are reaching out for help for your son. It sounds as though you have been very thorough with your responses to his behavior. However, as you stated, it is not working, it is not helping. Have you tried scheduling an appointment for him with a counselor? If not, that may be helpful.
Your son definitely violates physical boundaries. Does he also violate verbal boundaries by saying inappropriate things to girls or to others in general? That also can get him into trouble now and throughout his life. There many books available for teens about boundaries, how to respect people's boundaries, and how to have others respect yours.
What does "grounding" mean in your home? Did he have to stay home or go without his phone or electronics for a time? With most undesirable behaviors we want to change in children, we first have to find out what motivates them — what do they like to do when they have free time? Then, when the undesirable behavior occurs, we take away whatever motivates them. When they go for a long period of time without exhibiting the undesirable behavior, they can potentially earn back that privilege in small increments. We hope you are successful in finding the help your son needs.