Kit, I really want to joke that you should report that person to HR for sending you nasty messages on Teams. But seriously, I'm sorry you're having to deal with that. It sucks when you're dealing with interpersonal conflict at work. I'm kind of laying low with my boss right now because I'm worried he's pissed at me for dropping the ball on a project and I don't feel like dealing with that right now. In reality, we're probably fine. I hope things start looking better for you soon.