Maybe the power levels in the fanfiction are all wrong. Naruto has worked hard to achieve his strength, and if in the fanfiction, Team 7 members are given powers randomly without proper development, he could get fed up. For example, if Sakura suddenly becomes super powerful without any real training or explanation related to her character arc in the original story. Also, if the fanfiction has a dark and gritty tone that doesn't fit the spirit of Team 7 as Naruto knows it, that could be a reason.
The fanfiction might be changing the relationships within Team 7 too much. Naruto values his bond with Sasuke and Sakura. If the fanfiction makes Sasuke act like he doesn't care about Naruto at all, or Sakura is constantly mean to Naruto for no good reason, it would go against what Naruto expects from his team. He might be fed up with these false portrayals of the relationships he holds dear.
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.
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.
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.
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.
One reason could be that the fanfiction often portrays the characters in a very different way from how he knows them. For example, if it changes their personalities too much, it might make Naruto feel like it's not the same team he belongs to. Another reason could be the overuse of certain plot devices in the fanfiction. Maybe every story he reads has the same cliché situations, like the team always getting into the same type of trouble in a very predictable way. Also, if the fanfiction focuses too much on relationships that Naruto doesn't see as important within the team, it could put him off.
It could be due to Dumbledore's decisions regarding Harry. Sirius is very protective of Harry. If he thinks Dumbledore is using Harry in some way for the greater good without fully considering Harry's well - being, he would be fed up. For instance, Dumbledore's decisions about Harry's participation in the Triwizard Tournament could be a point of contention for Sirius.
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.
Perhaps Naruto quits Team 7 in the fanfiction because of a betrayal. He might find out that one of his teammates has been secretly working against him or has lied to him about something really important. This could shatter his trust in the team and make him want to leave. Or it could be due to an accumulation of small incidents. Like constantly being the one to get in trouble for the team's mistakes, or not having his opinions heard when it comes to team strategies. Over time, these little things can build up and make him feel that he's better off on his own.
Maybe he's tired of the same old dynamics. In fanfiction, sometimes the relationships in Team 7 can be written in a very repetitive way. For example, Sasuke's brooding and Sakura's one - sided love for Sasuke can become overdone, making Naruto feel sick of it all. Also, if the fanfiction focuses too much on the team's conflicts without any real development, it could be a reason.