One plot idea could be that as a girl, Sasuke is more open about her emotions from the start. She might form a different kind of bond with Naruto, perhaps a more sisterly or friendly bond initially. Another could be that she faces different challenges in the ninja world because of her gender. For example, some might underestimate her skills at first.
Well, in such a fanfic, a great plot could be that Sasuke, as a girl, has a unique fighting style that combines her traditional skills with a more feminine grace. This could attract Naruto in a different way. Also, the story could explore how her being a girl affects the Uchiha clan's expectations of her. Maybe she has to fight harder to prove herself worthy of the clan's legacy.
In this fanfic where Sasuke is a girl, the plot could involve a love triangle. With Sasuke being a girl, other characters might develop feelings for her. Naruto, on the other hand, might have to compete in a different way. Also, Sasuke could use her femininity to her advantage in espionage or diplomatic missions within the ninja world. For instance, she could charm her opponents into revealing secrets or making alliances, which would add a whole new dimension to the story.