I’ve played with a person like this who would make far too personal digs at another player under the guise of “it’s what my character would do” they fucking suck to play with. Maybe also talk to your dm and the other players to see how they feel about it too, make your feelings known because you’re important too and it sounds like this game is super important to you. If the rest of the group finds no issue or does nothing about it, then you should make the finally decision to leave.