So, it seems likely that our universe is just part of a bigger multiverse. Why this is a surprise to people, I am not sure. Our ancestors thought they where the only solar system, but now we know we are part of a much bigger galaxy. Then those galaxies are part of a much bigger galaxy cluster. So our universe just belongs to another, bigger-sized tier: the multiverse. However, the nature of a multiverse has many different theories from quantum gravity, quantum mechanics, and many other fields. I won't go into them all here.

One important question many people have about the multiverse is if we would have infinite other universes, or not. I believe there will only be a finite amount, and here's why. Say we have an infinite amount of universes. One universe must be absolutely perfect in every sense and measurement, like Plato's "Forms." Using the same logic, there must be an absolutely "unperfect" universe with absolutely nothing perfect about its measurements. This means there is a top end to all the universes, and a bottom end to all the universes, and a finite amount of universes in between (while the number of different combinations in measurements could be VERY large, it will not be infinity). Therefore, there must be a finite amount of universes in the multiverse because of that conclusion.

If you are in academia and can help me publish or get more attention to this theory/idea, please feel free to reach out. Thanks for reading!!