At the base of it, the TM is an abstraction built with sets and relations. Just like most computers are merely signals flowing around a circuit that get generated from other physical phenomena and will be transformed to other physical phenomenas. You can't hack around physical laws, or ignore the axiomatical rules in mathematics. The code that is not data are those things.
replyEverything else is data.
You are redefining both the term "code" and the term "data" in ways that I don't think most people would agree with - and more importantly, in ways that make it impossible to talk about von Neumann architecture.
replyBecause code and data as well as the von Neumann architecture are derived things, not fundamental stuff. The Turing Machine and Lambda Calculus are pure invention thats are logically sound. Almost everything else is downstream of that.
replyBy the time you get to programming language like C and LISP, and software like vim or firefox, everything is abstracted away and the only limits are self-imposed (or imposed by others that have done the work). They are not laws of nature.
So yes there’s a definition of code and data. But for the Turing machine, there’s only the tape and its content.