Gosh, what little I know about MM's family suggests nowhere near the level of dysfunction of the Windsors! I mean, her parents split when she was very young, but she lived with either her father or her mother throughout her childhood, and seems to have had an ordinary enough upbringing before going on to a well-regarded university.
Whereas Harry grew up with continual media scrutiny, his parents (both themselves with pretty dysfunctional upbringings) had a famously unhappy marriage, separated and divorced incredibly publicly when he was old enough to be aware of the publicity, including accusations of affairs, pregnancies etc with his nanny, was used as a cat's paw in his mother's love-hate relationship with the press as she fought popularity wars with Charles and the RF in general, lost his mother when he was still a child, and then will have spent years after her death unavoidably hearing lurid stories about her affairs, bulimia, suicide attempts, while in the not-so-tender routine of a boarding school etc etc.
I mean, you'd have to go a long way to cap that.