The theory that we are in a simulation, i.e. stuck in a matrix that is a subset of a bigger world running on what we would think of as a computer, is bullshit.
Being in a simulation of a bigger universe has a probability of strictly less than being in a "real" outer-most-level universe. This is because being in a simulation would still require a universe, and on top of that it would require a universe with sufficient technology to create "sub-universe" simulations.
We cannot create any sub-universe simulations. If we were in a simulation there is no reason not to expect this to recurse infinitely downward. I.e. knowing that we are at the "bottom-level" is evidence that that "bottom-level" is the "top-level."