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.
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.
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.
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.
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.
Naruto would likely be extremely hurt. He has always considered the Konoha 11 as his friends and comrades. So, at first, he would probably be in denial, trying to figure out what went wrong. He might try to talk to them, to understand their reasons.
In a 'naruto destroys konoha fanfic', one possible plot could be that Naruto is pushed to the edge by the villagers' constant mistreatment and the hidden secrets of Konoha's leadership. He discovers some dark deeds that the village elders have been involved in, like using him as a pawn without his knowledge. This betrayal could fuel his anger and lead him to decide to take revenge on Konoha.
Hinata would be heartbroken. She loves Naruto deeply and would likely try to understand his reasons. She would plead with him to change his mind, using her love for him as an argument, and maybe even offer to help him find a different solution to whatever problems he has with Konoha.
Well, it could be that the wielder of the Rinnegan has the ability to control powerful forces like the Six Paths techniques. They might use the Deva Path to create massive gravitational pulls that start to crumble the buildings in Konoha. Or perhaps with the Preta Path, they could drain the chakra from all the ninja in Konoha, leaving them defenseless against further attacks, which eventually leads to the destruction of the village.