Multiverse travel is very possible and relate directly to multiple dimensions.
What is mind-blowing about this to me is when we look down from our 3-d world to a 2-d world.
If we imagine a 2-d world (a plane with only width and length) populated with "flatlanders," height would be inconceivable to them. If we bent (curved) their world into a cylinder flatlanders would experience infinite length (or, they would return to the same spot each time they trotted off in a single direction). It would be completely unexplainable to them, and yet a fundamental part of their 2-d world. An attribute of the 3-d world which we never even think about, and yet unfathomable by flatlanders.
To me, that's humbling. Consider how inconceivable the 4th dimension is to us. Yet, it could be as simple and real as the 3rd dimension. We're just ignorant "moment landers" whose 3-d world is made possible by time.
Think about how 3 dimensions makes no sense without time. We can't perceive depth (3d space) without the time delay of light reaching us at different times (from nearer, farther objects).
Yet nobody can explain what "time" is. It's a fundamental element of the 4th dimension (in the same way height is fundamental to the 3rd dimension, and allowed us to bend a 2d world into a tube, completely unimaginable to the 2d flatlanders).
So, imagine if a 2d world was curved
almost into a tube, where the left and right edges of that world are just a nanometer apart. Flatlanders could stand at the edge of their world and never realize that if they just stepped across, they'd jump to the other edge of their world.
It's likely that we're just as ignorant of such capabilities regarding the 4th dimension (and 5th-10th dimensions). Such phenomenal capabilities (properties of the universe) might be right next to us, yet we can't see it.
For example, electrons (the particles that spin around atomic neutrons) exist in many places at once. We're made up of atomic particles. Does that mean we exist many places at once? (Getting into multiverse theory.).
When I consider how different our lives our today compared to 30 years ago, it makes me wonder what breakthroughs the next 2-3 generations will experience. I can't imagine living without immediate access to information/communication (internet). What will today's 5-year-olds view as unimaginable 50 years from now?