It could be that they are on a quest to uncover the truth about some ancient prophecy related to Konoha. They believe that the answers lie outside the village, so they decide to leave. Another reason could be that they are following a lead on a powerful enemy that has been causing problems in the ninja world, and they need to do it without involving Konoha directly.
Maybe they leave to find a better way to protect Konoha. They might think that by exploring the outside world, they can gain new knowledge and powers that will be useful for their village in the long run.
They might encounter various new adventures. For example, they could come across a hidden village with unique ninja techniques. They may also face powerful enemies that are unknown to Konoha. Maybe they'll find a mysterious ancient artifact that holds great power and has to protect it from those who would misuse it.
They could leave because of a prophecy. Some ancient prophecy might state that they need to leave Konoha to fulfill a greater destiny elsewhere. So they trust in this prophecy and leave their home.
Another reason might be that Naruto is seeking a greater purpose. In the fanfiction, his 'godlike' state could make him realize that there are threats out there that he can't face while being tied to Konoha. He may leave to protect the world on a larger scale, believing that he can be more effective away from the village.
They might leave because of a prophecy. If there was a prophecy that Naruto would bring destruction to Konoha or that Konoha would bring destruction to Naruto, Kushina might take Naruto away to prevent it.
Kiba would probably be shocked. He's Naruto's friend and also has a connection to Hinata. He might try to convince them to stay, saying things like Konoha needs them. But once he realizes they are determined, he would support them in his own way, like promising to visit them. As for Lee, he would see it as a very brave decision. He would be inspired by their courage to step out of their comfort zone and start a new life elsewhere.
It would be a huge blow to Konoha. Naruto is a hero in the village, and his departure would leave a big leadership void. The villagers would also lose a great source of inspiration. Hinata is from a respected clan, and her leaving would also have an impact on the clan's standing in the village. Morale among the ninjas might drop as they see two important figures leave.
Well, it would be a big loss for Konoha. Naruto is a powerful ninja, and his absence would mean one less strong fighter to defend the village. Ino, too, has her unique skills in mind - related jutsu and communication. Their departure might also lower the morale of other ninja, especially those who were friends with them or looked up to them.
One reason could be to seek greater power. Maybe they feel that Konoha no longer offers the training or resources they need to reach their full potential. So they decide to leave and explore other places where they can become stronger.
One possible reason could be to seek a new life away from the politics and pressures of Konoha. Maybe they feel restricted by the village's rules and expectations. Another reason might be for a personal adventure. They could be in search of something that Konoha can't offer, like a new type of ninja training or a mysterious power source. Also, it could be related to protecting their family. If they sense some kind of threat to their family within Konoha, they might choose to leave to keep them safe.
They could go to the Land of Fire's outskirts, where there are less - known ninja clans. Naruto might hope to learn from them and Anko could be interested in the unique fighting styles these clans possess.