Well, it might be that the fanfiction focuses too much on Sakura in a way that Naruto feels is unfair to the other characters. Naruto is part of a big world with many important people, and if the fanfic just hones in on Sakura all the time, he could get fed up. Also, if the fanfiction has Sakura constantly putting Naruto down or not appreciating his efforts like in the real story, that could be a reason.
It could lead to a shift in the type of fanfictions being produced. If Naruto getting fed up with Sakura fanfiction becomes a popular concept, more fanfic writers might avoid writing in that vein or might try to rewrite the relationship in a more acceptable way, which in turn changes the overall landscape of Naruto fanfictions in the fandom.
One reason could be that in some fanfictions, the characters of Team 7 are portrayed out of character. Naruto might be fed up if they make Sasuke too brooding in a way that doesn't seem true to the original. Also, if the fanfiction focuses too much on shipping within Team 7, like Sasuke and Sakura, and ignores Naruto's growth and importance, it could annoy him. Another possibility is if the fanfiction makes the team seem too dysfunctional in a way that doesn't match Naruto's view of his comrades.
Perhaps the fanfiction keeps rehashing the same tired storylines about Konoha. Naruto might be tired of seeing the same things over and over again, like always focusing on the village's dark secrets in a clichéd way instead of exploring new aspects of Konoha and its people.
If Naruto gets fed up with Team 7 fanfiction, some fans who love Naruto's perspective might stop reading those fanfictions. This could lead to a decrease in the popularity of certain types of Team 7 fanfictions. Writers might then have to change their approach to keep their readers.
Naruto might be shocked at first. He has always seen Sakura as a friend, so being beaten up by her would be unexpected. He could try to talk to her and figure out what's wrong.
One reason could be the lack of recognition he gets in the village despite his great contributions. In the fanfiction, Naruto might feel that his efforts to protect the village are taken for granted.
Perhaps Naruto is fed up with Konoha's fanfiction because he wants a new adventure outside of the village. He has spent most of his life in Konoha and might be craving for a change. He could be bored with the same old politics and power struggles within the village. Also, he may have realized that the ideals of Konoha are not as perfect as they seem, and this disillusionment makes him tired of it.
Yes, there might be such fanfictions out there in the vast world of fan - created content. However, it's important to note that fanfictions can vary greatly in quality and adherence to the original spirit of the Naruto series.
He could start to oppose the village's leadership more openly. Instead of being the village's hero who always follows orders, he might become a vocal critic. He might use his influence among the villagers to try and bring about change in the way the village is run. For instance, if he thinks the village is being too harsh on the younger generation of ninjas, he could start a movement to change the training methods.