One that's currently on air right now is: What's Wrong With Secretary Kim? It hasn't finished so I don't know if there's a happy ending but considering the genre/nature of the drama, I can say I'm 90% sure it will be happy. Also, the FL is the hottest and most fashionable and most capable one in the story. Honestly, her fashion is GOALS!
I'd say... a little different but Birth of a Beauty. She's the hottest one because she had plastic surgery to look that hot, but it's funny and cute with a very satisfying ending.
I think in Go Ho's Starry Night, she's the prettiest one. It's very cliched and kind of a wish fulfillment drama but it's meant to be as it's only a short one. Fun though. I really enjoyed the ML and FL's chemistry.
This one just ended and the FL in Lawless Lawyer is absolutely beautiful. She's fashionable, cool, smart and badass. It does have a happy ending too.
I think the FL in Suspicious Partner is the most attractive female character and she has a very happy ending too. I mean I think all 3 female characters are beautiful but you fall in love with her easily. She is so cute and pretty and charming.
The Legend of the Blue Sea is another one where the FL is super attractive and everyone knows that she is. I wouldn't say she's the most fashionable because she's a mermaid and doesn't really understand it at first, but as she grows so does her fashion sense.
I hope these help!