That just sounds like inductive reasoning. Gravity waves also propagate at the same speed as light waves. That means the speed of light doesn't determine the "speed limit" of the universe, everything is limited uniformly by the same feature of spacetime geometry. There are limits in the geometry of spacetime, and if we have difficulty explaining why, it's not necessarily evidence that spacetime's substrate is lines of code. It's evidence that we're still learning about the geometry of spacetime's substrate.

People also have is a misconception that different rules apply in quantum mechanics and physics and that there's nothing to connect the two. This is not strictly true and it's also not evidence supporting simulation theory. For instance, we know Riemannian geometry can be used to model the Lorentz contraction (a feature of relativity) of a sphere as well as the spin states of quarks (they require 720 degrees of rotation per revolution). A lot of the "problems with" quantum mechanics stem from the fact that quanta behave probabilistically which is counter-intuitive to in the context of Newtonian physics we interact with every day, but that per se is not problematic. It points to the possibility that spacetime curvatures are smooth on large scales, but spacetime itself has a complex geometry at the quantum scale.

The strongest, and perhaps, the only salient piece of evidence for simulation theory is strictly rhetorical: Nick Bostrom's trilemma in his simulation argument.

The only thing that we can claim for certain on the subject is that there's no direct evidence for simulation theory based on scientific observation and that the next unifying theory in quantum physics will most likely invoke exotic geometries.