Well my guess is that Meghan (now HRH the Duchess of Sussex) can actually charm anyone, including Princess Margaret if she was still alive. I also think that some of the portrayals and characterizations of Princess Margaret's peccadillos and personality do not take into account her positive attributes and her vulnerabilities.
That's a mater of opinion. Meghan hasn't charmed everyone, she certainly does not charm me.. and Margaret was fitful with people and erratic.. so I think its quite possible that Marg would find Meghan amusing one day and go sour on her the next..