@jens I agree with all you said. I have only one thing to add.
> The only thing a bully accepts is more strength than they can exert.
It's crucial how you use that strength. If you will try to beat them into submission, you fail. I rather propose to use that strength to become robust and resilient. You do not have to punch anybody. **You just need to be strong enough not to give an inch.** That it real strength.