The universe exists within the mind. There is no evidence to prove otherwise, as it's impossible, unless you are outside of the universe.
There is no need for the universe to materially exist. It's more efficient to create an illusion.
This coincides with quantum physics where atoms only exist when they are being observed, the universe magically appearing out of nothing into an infinite space, etc.
The universe could be a quantum computer creation, within a quantum computer creation, it could have been created by an artificial intelligent, infinitely intelligent being, within a quantum computer, within another quantum computer, etc.
It will be possible one day to nanoprint atoms to form anything... Why not a planet within 7 days? Why not a solar system? (in physical reality)
It will be possible one day to create a metaverse, a universe within a quantum computer, with the help of artificial intelligence.
Who is to say that this whole universe, up to this very moment that you are reading, wasn't created right now, with your memories all programmed? How do you know what is reality?