Perhaps Sasuke travels to a future time where the ninja world is on the brink of destruction due to a new, powerful enemy. He then has to use his knowledge from his own time to find a way to save the world. This would put him in a situation where he has to cooperate with new generations of ninjas and also face the consequences of the actions in his own time.
Another plot could be Sasuke traveling to a time when the Hidden Leaf Village was first founded. He could interact with the first Hokage, Hashirama Senju, and learn about the origin of the village's power structure and the Uchiha's place in it. This would give him a new perspective on his clan's history and his role in the ninja world.
One idea could be Sasuke traveling back to the Uchiha massacre. He might try to prevent it, which would completely change the Naruto storyline. This could lead to him having to face off against Itachi in a different context, not as an avenger but as a protector of his family.
They could also travel to a time during one of the great ninja wars. They might get involved in battles they previously only read about in history books. Sasuke could team up with his ancestors and Sakura could learn new medical techniques from the medics of that time. This would not only change the course of the war they are in but also bring back new knowledge to their own time.
One idea could be that Sasuke and Hinata travel back to the time when the Uchiha clan was still intact. Sasuke gets to see his family again and Hinata witnesses the power and unity of the Uchiha. They might try to prevent the tragedy that befell the Uchiha clan. Another plot could be them traveling to a future version of their world that has been completely destroyed. They then have to figure out how to go back in time to change the events that led to this destruction.
One idea could be that Sasuke and Sakura travel back to their childhood days. They could then use their knowledge of the future to prevent certain tragedies from happening in the village. For example, they might stop the Uchiha massacre, which would change the entire course of Sasuke's life and their relationship.
Another plot could be that they travel to a time when the Akatsuki was first formed. Naruto might try to persuade the members to choose a different path. Sasuke could explore the reasons behind the Akatsuki's creation more deeply. Sakura could use her skills to heal some of the wounds that led to the formation of the Akatsuki in the first place.
One idea could be that Sasuke and Hinata travel back to the time when the Uchiha clan was still alive. Hinata could use her Byakugan to sense the unrest in the clan before the massacre. Sasuke, with his knowledge of the future, might try to prevent the tragedy, and during this process, their relationship deepens as they work together.
One idea could be that Sasuke and Sakura travel back to the time when the Uchiha clan was still alive. They could try to prevent the massacre. Sasuke might have the chance to talk to his parents and change the fate of his family. Sakura could use her medical skills to help those who were injured during that chaotic time.
Another plot could be that they travel to a time during a great war in the past. In their ANBU capacity, they join the fight on the side of the Leaf. Along the way, they meet younger versions of their own teachers and comrades. They might discover secrets about their families or clans that were lost over time. This time travel experience could also make them re - evaluate their relationship with each other and the Leaf Village as a whole.
One idea could be that Sasuke goes back in time and tries to prevent the Uchiha massacre. He could use his knowledge of the future to stop Itachi from carrying out the order. Another could be that he goes back to his early days at the ninja academy and tries to change his relationship with Naruto from the start. Maybe he would be more open and friendly, which could change the whole dynamic of their rivalry.
One plot idea could be that Naruto and Sasuke keep reliving the day of the final battle. Each time loop, they gradually discover hidden secrets about their pasts that change their relationship. For example, they might find out that there were other forces at play that made them enemies in the first place.
Perhaps Sasuke travels back to the very beginning of the series. He could choose to befriend Naruto right from the start, which would completely alter their dynamic. He could also use his advanced skills to quickly rise in the ninja ranks and start to influence the political situation in the Hidden Leaf. This would lead to a very different story as he tries to prevent future tragedies and build a stronger, more united ninja world.