Not an expert (just a humble physics bachelors) but the problem isn't of whether you can "fit" one into the other: the real line (0,1) is in one-to-one correspondence with the whole real line, for example. The problem is that no infinite system can be simulated by us mortal finite beings.

For a slightly more boring situation: The Church-Turing-Deustche principle states if you assume every physical process can be completely described by quantum mechanics, then every finitely realizable physical system can be simulated by a universal quantum computer. So if you don't mind a reasonable finite approximation to whatever physical system you're interested in simulating, and you have the means to build a machine that can simulate them, there you have it.

Something else I heard on the passing: Apparently a string theorist had found what looks like error-correcting codes in his work (https://www.space.com/32543-universe-a-simulation-asimov-debate.html). Now I don't know what that means, cuz I know 0 string theory. But maybe it shows our universe itself is simulated (wherever the damn thing is running), who knows lol