[A/N: I will try to add other ideas that have nothing to do with Naruto from now on.]
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Adult Sasuke (Boruto Sasuke) travels to different world with the help of his Rinnegan.
You can have Sasuke visit other worlds like Fairy Tail, Highschool DxD, Bleach, Danmachi and many more.
Sasuke will not be able to learn or use different forms of energy or magic from other worlds. He can only use his original abilities from the Naruto world so no magic or shinigami powers and shit like that.
Pretty much Sasuke goes to other worlds and gets involved in the main story of that world.
For example you could have him join Fairy Tail or join one of the familias in Danmachi.
You want to keep Sasuke's personality the same as it is in Naruto.