Another reason could be related to his moral beliefs. Naruto might see the Kyuubi's chakra as something that was forcefully sealed within him against the Kyuubi's will. Using it could seem wrong to him from an ethical perspective, like taking advantage of a captive's power.
One possible reason could be that Naruto fears losing control. The Kyuubi's chakra is extremely powerful and has a mind of its own. Naruto might be worried that if he uses it, he'll go on a rampage and hurt his friends or innocent people.
His friends might respect his decision more. They know how powerful the Kyuubi's chakra is, but also understand Naruto's reasons for not wanting to use it. This could strengthen their bond as they see Naruto's integrity.
One possible reason could be that Naruto might feel he doesn't fit in with the members of Team 7. Maybe he has some personal goals that he thinks he can't achieve while being on the team. For example, he might want to focus more on individual training to become stronger in a specific area like mastering a certain jutsu, and he believes being on a team would be a distraction.
One possible reason could be that Naruto is too focused on his ninja duties. He has always been dedicated to protecting the village and his friends, and marriage might seem like a distraction from that. For example, he has to constantly be on guard against new threats and train the next generation of ninjas.
One possible reason could be that Naruto feels betrayed by Konoha. Maybe he discovers some dark secrets about the village that make him question whether it's worth protecting. For example, if he finds out that the village elders were involved in unethical experiments or unjust actions against certain groups. Another reason might be that Naruto has different ideals now. He could believe that there are more important things in the world than just protecting Konoha, like bringing true peace to all nations without focusing on one village's interests.
Perhaps Naruto has found a new purpose or community outside of Konoha that values him more. He may be so content with his new life that he simply doesn't want to get involved with Konoha's problems anymore. Konoha's actions towards him could have made him realize that his loyalty was misplaced all along.
One possible reason could be that Naruto feels betrayed by Konoha. Maybe he discovers some dark secrets about the village's leadership or past actions that make him question whether Konoha is truly worth saving. For example, if he finds out that they were involved in unethical experiments or unjust treatment of certain clans. Another reason might be that he has been pushed too far by the villagers' continuous mistrust and discrimination towards him, despite all he has done for them. So he decides he's had enough and refuses to save the village that has not fully accepted him.
It could also be that Naruto has grown disillusioned with the politics in Konoha. Constant power struggles, nepotism, or unfair treatment of certain groups within the village might have pushed him away. He might feel that his help would only be enabling a corrupt system.
One possible reason could be that Naruto has some kind of misunderstanding with Kakashi. Maybe he saw Kakashi do something that he misinterpreted, and it made him so angry or disappointed that he refuses to call him sensei.
It could be that Naruto is under some sort of external pressure. Maybe there are other people in the village who don't trust Sasuke and Naruto doesn't want to go against the village's wishes. Or he might be worried about Sasuke using the knowledge he teaches for the wrong purposes. Naruto has always been about protecting the village and he doesn't want to put it at risk by teaching Sasuke if he's not sure of Sasuke's intentions.
Another reason could be that Jiraiya has some doubts about Naruto's readiness or potential. He might think that Naruto is not yet at the level where he can fully benefit from Jiraiya's training. For example, Naruto may lack some basic skills or knowledge that Jiraiya believes are necessary prerequisites for his more advanced training.