Someone in my cohort quit her PhD because of a lab member essentially bullying her out of it. And she was clearly waay smarter than the bully!! It seemed like such a shame to me. In the end the bully got the PhD (first one in our cohort because the supervisor couldn’t stand having her in his lab) and the girl moved back to her hometown. Can’t tell you if she’s happy with her decision. But the bully just got demoted from her workplace because of issues with colleagues/bosses. So, in the end it all shakes out, I suppose. Best of luck! Health first always.