I wish I understood it better.
Me too but... It would still be some form of mathematics as soon as you tried to write it down in a neat, precise way for others to understand it. Maybe exotic math, but still math :p
Saying that sure, they evolve like ours, and sure they affect ours, but even so they are not real - that is I suppose one stance, but then you are getting pretty close to solipsism.
No, you'd get something like Bohmian mechanics, or Rovelli's relational interpretation. Which is my point: you can only take this as evidence of other worlds if you basically smuggle those assumptions in.
Is there any hope that one could actually do this? The article mentions that large systems may be self-observing (via gravity).
One location in the latent space of a latent diffusion model is a view into a universe that is as real as ours. That half cat, half dog monstrosity you accidentally created. It exists as a drawing, or as a physical mass of flesh, with every possible back story as to how it got there. And also every possible future.
edit- brain fart
But what are the worlds?
My feeling is that Max Tegmark has it right. Everything is mathematics.