One common theme is redemption. Since they have a new chance at life through reincarnation, often Sasuke gets a chance to atone for his past mistakes. For example, in some fanfics, he uses his new life to make up for the pain he caused in his previous life.
One popular 'Naruto and Sasuke reincarnation fanfiction' is 'Reincarnation of the Uchiha Brothers'. It has an interesting plot where Naruto and Sasuke are reincarnated in a different era and have to deal with new threats while still having a strong bond from their past lives.
Sasuke's adaptation would be a long process. He'd start by observing the daily lives of wizards. He'd notice how they use magic for simple tasks like lighting candles or cleaning. In contrast, in his past life, he'd use ninjutsu for such things. He'd have to get used to the fact that he can't just rely on his Sharingan all the time. He might attend classes at Hogwarts and learn about different spells. At the same time, he'd be constantly comparing the magic here to his ninja skills. As time goes on, he'd start to blend in more, using magic in his own unique way that combines his ninja - like thinking.
One possible plot could be that Harry, after his death in the Harry Potter universe, is reincarnated as Sasuke in the Naruto world. He would then have to deal with Sasuke's past traumas and his own new set of ninja skills and challenges. He might use his knowledge from the wizarding world in unexpected ways in the ninja world, like using magic - like spells that are disguised as ninja jutsu.
Yes, there might be such fanfics out there. In the Naruto fandom, with a large number of fans creating various types of stories, it's possible that some would write a story where Naruto destroys Sasuke in a way that could be seen as Sasuke - bashing. However, these kinds of fanfics may not be in line with the overall spirit of the original work which focuses on their complex relationship and growth.
In the 'naruto is protected by sasuke fanfiction', Sasuke's protection of Naruto could be multi - faceted. Sasuke, being a powerful ninja, would first of all use his physical strength and speed to block attacks aimed at Naruto. Emotionally, his bond with Naruto would make him extremely vigilant. He might sense Naruto's distress from afar and rush to his aid. In terms of strategy, Sasuke would likely plan their movements carefully when they are in dangerous situations, ensuring Naruto is always in a relatively safe position. His ability to quickly analyze a battle situation and react accordingly would be crucial in protecting Naruto.
Well, in some fanfictions, Naruto might be promoted over Sasuke because Naruto has always been seen as the more positive and inspiring character. He has a strong will to protect his friends and the village, and his growth throughout the series is more in line with the traditional hero's journey. His ability to make friends and bring people together could be a reason for his promotion in the fanfiction.
In proper fanfics rather than 'lemon' ones (as 'lemon' implies inappropriate content), Naruto is known for his never - give - up attitude. He's the heart of the story, always trying to bring Sasuke back and protect his friends. Sasuke is a complex character, with his family's past haunting him, which makes him seek power and revenge at times. Sakura, she starts as a girl with a crush but evolves into a capable ninja. These characteristics are often the foundation for fanfic authors to create interesting stories that don't involve improper content.
It might be for Naruto's own good. Sasuke may believe that Naruto is on a dangerous path that will lead to his downfall. So he captures him to keep him from making bad decisions, like sacrificing himself for the village or something similar. He wants to save Naruto from himself in a sense.
In some fanfictions, Naruto might reject Sasuke because of Sasuke's continuous pursuit of power in a way that endangers others. Naruto, who values friendship and the safety of the village, could see this as a betrayal of their shared values.