There's a chance that it could be an old enemy of Naruto's, like Orochimaru, who has found a new way to cause chaos. He could be using some new jutsu or mind - control technique to make Naruto believe that Konoha is his enemy and use him to further his own evil plans.
It could be a corrupt elder in Konoha. They might be power - hungry and see Naruto as a threat to their control. So they manipulate the situation to make Naruto the enemy.
Maybe it's a new villain who has a grudge against Konoha and frames Naruto. This villain could be from a clan that was wronged by Konoha in the past. They use Naruto as a tool to take revenge on Konoha by turning him against it.
It could be a rogue ninja from within Konoha who has embraced the 'darkness' fully and wants to reshape the village according to his own twisted ideals.
The main antagonist could be a new character. For example, a powerful ninja from a rival village who has a vendetta against Konoha. This ninja could manipulate Naruto into leaving Konoha by spreading false rumors about the village. Then, he tries to use Naruto's power as an assassin for his own evil plans.
It could be a long - lost relative of one of the old villains like Orochimaru. Maybe this person has been in hiding, training and growing in power, and now wants to take revenge on Konoha for what happened to their family member.
Maybe the main antagonist is a powerful figure within Konoha who doesn't want Naruto to leave and become an independent force. He secretly sends assassins after Naruto. When Temari gets involved, this figure also targets her. His actions are driven by his thirst for power and fear of Naruto's potential outside of Konoha's control.
Perhaps it's an old enemy who has somehow managed to come back stronger. Maybe someone from Orochimaru's old experiments that went wrong, but instead of dying, they gained some dark and powerful abilities. They see Naruto's return as a threat to their plans of world domination, so they target Konoha first. They might be able to control dark chakra in a way that no one has seen before, and use it to create chaos and destruction. They could also have some minions who are equally as powerful and loyal to them, making them a formidable foe for Naruto and Konoha.
The elders of Konoha could be the main antagonists. They might be the ones who have been neglecting Naruto all along, and when he leaves, they see him as a threat to Konoha's stability.
It could be an evil version of Sasuke. Maybe he has fallen completely to the dark side and manipulates Naruto into destroying Konoha. Or it could be Orochimaru who has found a new way to control Naruto's actions from the shadows.
It could be a rogue ninja from a neighboring village who has a vendetta against Konoha. This ninja might see Naruto's return as an opportunity to take on the strongest ninja in Konoha and prove his own strength.
The Konoha elders could be the main antagonists. They are often shown to be quite traditional and set in their ways in the original series. If Naruto goes against their old - fashioned ideas about the village's future and ninja code, they would likely oppose him strongly and could be the driving force behind making Naruto an outcast, which in turn could lead to his 'betrayal'.
It could be Orochimaru. He has always had his eyes on Konoha and might find a way to manipulate Naruto into attacking it. Maybe he uses some new experimental jutsu on Naruto to make him do his bidding.