Interesting that Meghan's been married to Harry for 7 yr. and it's only with her show that she decided to go by Meghan Sussex. Taz is correct when she brought up the point that Meghan whined to Oprah that when she married she gave up her "independence/identity", she couldn't stand the Royal duties, but she gladly accepted the titles. We know why.
I'm sure it was because she was receiving flak about flouting the Duchess title so she "changes" her name to Meghan Sussex...for the kids, of course. It's true, the title was given to Harry by his grandmother, but he doesn't count.
This way she can say, "I'm Meghan Sussex....I'm the Duchess of Sussex, by the way." As if no one knows that. In all these years, she was referred to as Meghan Markle without a peep from her. It's all for the show.