Another reason could be that Naruto is on a self - discovery journey. He feels that he has learned all he can in Konoha and needs to experience the outside world to grow further. Running out of Konoha is his way of starting this new adventure and finding out more about his powers and his place in the ninja world.
One possible reason could be that Naruto feels misunderstood in Konoha. Maybe some villagers still hold grudges against him despite his efforts to protect the village. He might run out to find a place where he can truly be accepted for who he is.
Perhaps Naruto discovers a dark secret about Konoha that he can't bear to be associated with. This could be something related to the political underbelly or a hidden past event that goes against his values. So, he runs out to distance himself from it all.
Another reason could be that Naruto is being targeted by a powerful enemy within Konoha. He doesn't want to put his friends and the village at risk, so he runs away to draw the enemy away from Konoha. This would show his selfless side, sacrificing his own safety for the greater good of the village.
One possible reason could be that Naruto discovers some dark secrets about the village leadership that go against his values. For example, if he finds out that they have been using underhanded means to maintain power.
In fanfiction, Naruto might snap at Konoha if he feels betrayed by his friends or the village. For example, if they don't support him when he tries to make important changes or if they side with someone who has wronged him. Also, if the village starts to become too controlling or authoritarian in the fan - created story, Naruto, with his free - spirited nature, would likely snap.
Maybe Naruto has seen too many unrealistic or out - of - character portrayals of Konoha in the fanfiction. For example, some might make Konoha overly cruel or its people too stupid, which goes against his understanding and love for his village.
One possible reason could be a sense of disillusionment. Maybe Naruto discovers some dark secrets within Konoha's leadership that make him question his loyalty. For example, if he finds out that some decisions were made that put the village at risk for the wrong reasons.
One possible reason could be the pressure he feels in Konoha. Naruto has always been an outcast in the village to some extent. People used to fear and shun him because of the Nine - Tails inside him. He might feel that running away would be a way to escape all that negative attention and find a place where he could be himself without the constant reminder of his 'otherness'.
Perhaps she is being chased by some unknown enemies in Konoha who are after her for some reason. She might think that running away from Konoha is the only way to protect herself and those she cares about. It could also be that she has a new mission or purpose that she believes can only be achieved outside of Konoha, and she is willing to sacrifice her life in the village for it.
One possible reason could be that Naruto discovers some dark secrets about Konoha that shatter his idealized view of the village. Maybe he finds out that the village elders were involved in unethical practices, like using shinobi for immoral experiments. This would make him lose faith in Konoha and decide to leave.
One possible reason could be to search for a powerful artifact. In many fanfictions, there are often hidden and powerful items that can change the fate of a village or even the whole ninja world. Naruto and Tsunade might leave Konoha to find such an item before their enemies do. This would be a dangerous mission, so they keep it a secret from the rest of the village to avoid panic.
One reason could be that the fanfiction might have misrepresented Naruto's character. He's a complex character with strong values, and if the fanfiction twisted those, he'd have enough. For example, if it made him out to be too subservient to Konoha when he's always fought for change within the village.