The Hokage, whoever it is at the time, would see Naruto's actions as a major threat. They would likely assemble the ninja forces to defend Konoha. But there would also be a part of them that would wonder what drove Naruto to this. Kakashi, for example, would be conflicted. He has a deep bond with Naruto, but he also has a duty to protect Konoha. So he would try to find a way to end this without harming Naruto too much.
Sasuke would likely be very conflicted. On one hand, he has his own complex relationship with Konoha, but on the other hand, Naruto is his friend. He might initially try to stop Naruto, thinking that there could be another way. Kakashi would be shocked and heartbroken. He has always believed in Naruto and would try to understand what led Naruto to this point while also trying to stop him.
One possible plotline could be that Naruto is somehow corrupted or misled. Maybe he discovers some dark secrets within Konoha that he believes can only be resolved by its destruction. As for the Alvarez Empire, they might see an opportunity to expand their influence in the chaos Naruto creates and form an uneasy alliance with him at first.
The younger generation, like Sakura and the other ninja trainees, would be terrified. Some might be angry at Naruto and Kushina, while others might be more confused. Sakura, in particular, might feel betrayed as Naruto was her friend and teammate. But at the same time, she might wonder if there was a good reason behind their actions and struggle with her loyalty to Konoha and her feelings for Naruto.
Naruto would probably be conflicted. On one hand, he has a deep love for Konoha, his home. But on the other hand, he might have been hurt by the past events that led to his departure. He could initially be hesitant, but eventually be swayed by the thought of seeing his friends again.
One reason could be that Naruto has seen too much death and destruction in Konoha. His 'godlike' state might make him think that the only way to end all the suffering is to destroy the root cause, which is Konoha. He may believe that Konoha's system is so broken that it can't be fixed and needs to be completely eradicated.
Sasuke might be more understanding. Given his own experiences of leaving Konoha, he could respect Naruto's decision. However, he might also secretly plan to keep an eye on Naruto from afar to make sure he is safe.
Sasuke would likely be conflicted. On one hand, he has his own issues with Konoha, but on the other, he might be surprised that Naruto, who was always so loyal, would give up. He could try to understand Naruto's reasons or maybe even join him depending on the situation.
It could be Sasuke. If he were to turn to the dark side in the fanfiction, his Rinnegan powers could be used to destroy Konoha. He has the potential to be extremely powerful and if he has some sort of vendetta or is influenced by some dark force, he might take his anger out on the village.
Sakura would probably be very worried. She has always cared about Naruto deep down, so she might be constantly trying to find a way to bring him back. Kakashi, on the other hand, would likely understand Naruto's reasons to some extent. He might be sad but also respect Naruto's decision. As for Sasuke, if he is in the village at the time, he could be conflicted. He and Naruto have a complex relationship, and Naruto's leaving might make him realize how much Naruto actually means to him.
The older generation, like Tsunade, would be horrified. They've seen Konoha through many hardships and would not want to see it destroyed. They would likely mobilize all available forces to stop Naruto and the Kyuubi. Meanwhile, Naruto's friends like Shikamaru and Choji would be in shock. They've always known Naruto as a kind - hearted and loyal friend, and this sudden turn would be very difficult for them to accept. They might initially be in denial and then try to find a way to stop Naruto without harming him.