Oooo, you're right, so many good options. Boba Fett instantly comes to mind for me too, specifically this version from war of the bounty hunters:
I mean the vibes are outstanding. Vader is iconic but I'm not sure the word 'aesthetic' really works for him. Really subjective I guess. Padme, Lando and Maul also come to mind all for completely different reasons. Din Djarin does have a strong aesthetic, if a bit of a boring one. Maybe I'm a bit biased after just finishing Andor, but Mon Mothma looked fantastic in every scene she was in, and she definitely wore very similar dresses that gave her a very particular aesthetic.
...or maybe Genevieve O'Reilly is just gorgeous.
When it comes to an aesthetic that really feels like Star Wars, though I think Boba is my pick.