In a fanfiction, Naruto could also give up his dream due to the discovery of a dark secret about the Hokage position. Maybe he finds out that the Hokage has to make sacrifices that go against his moral code. This realization could make him step back from his long - held dream of becoming the Hokage.
Another reason might be the loss of important people. If someone like Iruka or Kakashi, who were his pillars of support, were to die in a way that made Naruto feel it was all in vain, he could give up. He might think that without them, his dream doesn't matter anymore.
Perhaps the death of a key person in his life could lead to him abandoning his dream. If someone like Iruka or Kakashi, who were important mentors to him, died in a way that made Naruto question the purpose of his dream. He might think that without their support and guidance, his dream was no longer worth pursuing.
One reason could be the constant setbacks he faces. He might feel that no matter how hard he tries, he can't achieve his goal. For example, if he fails too many times in battles against strong opponents, he could lose hope. Another reason might be the loss of important people in his life. If someone like Iruka or Kakashi, who have been his pillars of support, were to die, it could shatter his dreams as they are so closely tied to his will to succeed for their sake.
One reason could be curiosity. They may be curious about how fans are portraying them and their relationship. Another reason is to get inspiration. Fanfiction can have some really creative ideas that they might use in their own content.
One reason could be to show his maturity. Smoking is sometimes associated with adulthood or a more worldly view. So, by having Naruto smoke, the author might be trying to show that he has grown up and is dealing with more complex issues.
One reason could be that Naruto has always been more attracted to those who understand his outcast past better. Sakura doesn't really have that kind of connection with him as she comes from a more normal background. So there's a lack of that fundamental understanding between them which hinders any romantic feelings.
One reason could be the fear of losing his friends. Naruto has always been very protective of his comrades. In some fanfictions, he might face a situation where he is on the verge of losing them, like a powerful enemy threatening to kill them all. This would make him afraid as his friends are his most precious things.
One possible reason could be a miscommunication between them. Maybe Anko feels neglected and then strays. Another reason might be that the writer wants to create a more complex and angsty plot.
A reason could be that Itachi is framed as a traitor to the Leaf Village in the fanfiction. Naruto, being the defender of the Leaf, would then see Itachi as an enemy and take action to kill him to uphold the village's safety and honor.
One reason is that some fanfiction authors may lack a deep understanding of Naruto's character. They might write things that are completely contrary to his values and personality just for the sake of creating a 'unique' story. For example, Naruto is known for his positive attitude and strong will, but in some fanfictions, he could be depicted as a negative or spineless character.
One reason could be that some fans are very purist about the original Naruto story. They might feel that fanfiction often distorts the characters or the plot in ways that go against the essence of what Naruto is all about. For example, changing a character's personality completely to fit a romantic or dark and edgy narrative that doesn't align with the source material.