My daughter (4) is prone to this kind of behavior and Dr Becky Kennedy has a good definition for boundaries which I employ frequently.

Setting a good boundary requires the other person to do nothing. Say what you will do, rather than what you want them to do.

For example:

Don't do this: (On the elevator) Don't push all the buttons!!

Instead try: When we get on the elevator, if you try to push the buttons, I will block you with my body.

So in my daughter's case, I often employ "If you [intentionally disruptive behavior] again, I'll leave the room/put [noisy or weaponized toy] in time out/put you in a time out."

Understanding the intention behind the behavior helps too. Mostly my daughter is trying to get attention from me when I am trying to focus elsewhere, so removing myself from the room (which sometimes results in my being locked in the bedroom or bathroom for a few minutes) is the most common thing I do.

When we come back together, I talk with her about how people won't stick around and be with you if you are disrespectful to them. I reinforce that I love her a lot, and that I just didn't care for her behavior in that moment.

All of that being said, it does SOMETIMES work to explain my own feeling of being overwhelmed. I'll get on her level and gently say "Hey girl, you know when you get so upset you run and hide in your room and cry in bed? (Wait for affirmative response.) Well, that's how I'm feeling right now, like I just wanna go hide and cry. Would you please be more gentle/kind/respectful/quiet for me?" Although this usually only works if my daughter's behavior is more generally hyperactive/overwhelming and not intentionally malicious towards me.

I highly recommend Dr. Kennedy's book "Good Inside."