Another reason might be related to his pursuit of power. If in the fanfiction, Naruto is constantly facing stronger enemies and he believes that his current strength is insufficient to protect those he loves, he might attempt to sacrifice himself in a desperate attempt to gain more power, like through some dangerous and forbidden jutsu.
One possible reason could be his overwhelming guilt. Snape had a complex past, being involved in the Death Eaters and then switching sides. He might have felt that he could never truly be redeemed, especially with all the lives lost during the wizarding war that he had some part in, whether directly or indirectly. This guilt could have driven him to such a desperate act.
One possible reason could be the extreme pressure he faces. Merlin has to constantly hide his magic in a world where it's feared and persecuted. This secrecy and the fear of being discovered might have built up to a point where he feels there's no way out. Also, his loyalty to Arthur might play a part. If he feels he has failed Arthur in some way, like not being able to protect him fully from threats, it could lead to such despair.
One possible reason could be his thirst for power. He might see Naruto as an obstacle in his pursuit of greater strength. Maybe he believes that by eliminating Naruto, he can prove himself to be the stronger one and gain more recognition in the ninja world.
There are several reasons. He might be afraid of getting too close to people because he's lost someone important and is scared of more loss. It could also be that he's discovered some new power within himself that he doesn't understand and is worried about hurting others if he gets too involved. Additionally, there could be some political intrigue in the village. Maybe there are some people who are plotting against him and he's keeping to himself to avoid being a target or putting others in danger.
In fanfics where Naruto attempts suicide, it could be due to extreme loneliness. He has often faced isolation in the original story, and in some fan interpretations, that feeling could be amplified to a point where he sees no way out. Another reason might be failure. If he fails in protecting his friends or achieving his goals in the fanfic's alternate storyline, he could feel so despaired that he contemplates suicide.
Maybe the friend betrayed the village in a really bad way. In the Naruto universe, loyalty to the village is important. If the friend joined the enemy and was causing great harm, Naruto could see killing them as a last resort. For instance, if they were about to give away crucial secrets that would lead to the destruction of the village.
One possible reason could be the burden of his past. Naruto has faced a lot of hardships and the memories might be overwhelming him, making him want to be alone. For example, the loss of his master Jiraiya might have left a deep scar, and he might feel that isolating himself is the only way to deal with that pain.
Maybe he feels a sense of guilt. For example, if something bad happened in the village that he blames himself for, even if it wasn't really his fault. He could exile himself as a form of self - punishment. He has always been very hard on himself when it comes to the well - being of the village and his friends.
One possible reason could be fear. Naruto has the Nine - Tails inside him, and the villagers might be so afraid of the power of the Nine - Tails getting out of control that they decide to take extreme measures. They might see Naruto not as a person but as a potential threat that needs to be eliminated.
One possible reason could be to gain more power. Maybe he thought that emotions were holding him back from reaching his full potential as a ninja. He might have seen other powerful ninjas who seemed to be emotionless and thought that was the way to go.