There is no isomorphism within the Platonic realm either, each concept is unique.
The formalisation of 2+2=4 as just symbols is different to the concept of two plus equals four, which is turn different from another concept using the symbols 2+2=4, which is in turn different to a translation of two equals two equals four form one language to another.
I'm not speaking about a correspondence to the physical realm, but rather the distinction and identity of different concepts or meanings
within the Platonic realm. One concept is never another, is not doing the same thing as another. I'm talking about the necessary distinctions of the platonic realm, which render isomorphism incoherent.
To assign isomorphism in Platonic realm is to tell a falsehood about the distinctions of the Platonic realm. A ToE is impossible because it cannot cross distinction. Whether in the physical or Platonic realm, any proposed ToE is but one distinction of reality. In being the ToE, as opposed to everything else, it necessarily leaves something out. It always fails to cover of something the distinction which are not it.
Put simply, it does not matter how complex or not a string might be, for in being itself, it is distinct from everything else. The problem isn't given in the particular length or cycles a representation might have or not, it is that
the representation is never thing it describes. Full detail is the only description to give, whether we speak of a physical state or something in the Platonic realm. There can be no "shorter strings" of description, derivation form outside concept or formalisms. Any thing, physical or Platonic, can only be given by itself. Our descriptions only give an account of this thing when it describes
it.
This does no imply randomness. It is not, for example, make 2+2=4 random. Since it is given by the concept itself, it is the nature of
that instance of 2+2=4 to have this particular meaning. The same is true of every instance of two plus two equals four. The same is true of every concept of translation between two symbolic languages.
Whether the definitions of the Platonic realm or instances of measurement of the physical universe, there is a
reason are present as such: that what each of them are/do. One was never gong to have a world in which an instance of 2+2=4 meant something else than it does. Same for 2x2m pavers one is using in their backyard. If you've got a 2x2 meter paver, it's was never going to be anything else.