Got some ideas
Rimuru encounters a black hole and is drawn into a different world.
With the existence of the Great Sage, Rimuru will only have one more skill that can travel through time and space.
Rimuru will not go out of his way to change anything, but he will not turn a blind eye when something is unreasonable.
The worlds he travels through are basically anime. There are worlds that Rimuru knows about, and there are also worlds that he doesn't know.
The story of a world will not be too long. After all, Rimuru is a traveler and a bystander. To the protagonist of that world, he is a passerby.