It looks to me as if she went to Wimbledon as "Meghan" and not as "The Duchess of Sussex". I love that she went with her friends to enjoy a game of tennis and have a laugh or two with said friends. Her dress is just Meghan and she's not in the Royal Box.
That is not to say that she was not dressed appropriately, I loved her ensemble, especially her blazer even if it no longer fits as well as it used to and her hat which doesn't seem to fit as well as it used to either which would not be surprising if she is still breastfeeding.
Days like this won't come often for Meghan and seeing her sitting in the 'cheap seats' wearing her signature hat and having a ball with two ghosts is pure gold.