As I understand it, there were preliminary and probably not serious conversations at Dior about doing something with Meghan; she got over-excited and had her people put it out to the press; Dior said, Sorry but we were just never that into you.
Meghan is pretty but she doesn't have the face or body for one of the high fashion houses, not many mortal humans do have that rare and exquisite combination of genetics that is 'the look'. Also, wrong ethnicity in 2025. Haute couture and luxury brands are mainly using Asian especially Chinese and Korean models now for women because the Chinese and South Koreans are pretty much the only nation left with an upper middle class with lots of disposable income, who are (sadly) desperate to look Western. That's why all the K-pop girls are getting the big modelling gigs.
High fashion isn't racist necessarily (just utterly misogynist) but if they want a Black female model they'll go for a dark-skinned over a light-skinned woman because they photograph so strikingly and, also, because there's disposable income in the elite social classes of many African nations too.
Also, ALL the high fashion houses are obsessed with British royalty, I don't know why, they just are. Any royalty, really. So Meghan destroyed any chance she had of being the face of anyone decent when she did Oprah and Netflix. She also apparently pissed off Edward Enninful, I don't know the details, and he's not exactly a difficult man to piss off, but anyway she did. So that ruined Vogue for her.
Meghan just doesn't have the body for high fashion, nothing wrong with that, most of us don't. She has a square torso and not much waist. She looks lovely in flared dresses that give the illusion of a waist and minimise her shoulders which are quite broad; why she insists on body con and those execrable high-waisted belted pants suits I do not know. Kate suits those looks because Kate is willowy.