> If I had to say one text that is the fundamental one, I would go with a paper: “On Computable Numbers, with an Application to the Entscheidungsproblem” [1], by Alan Turing

Certainly that one, but I would add a couple of others:

"https://en.wikipedia.org/wiki/The_Laws_of_Thought" (George Boole) - lays out boolean algebra; fundamental to everything in computing

"https://en.wikipedia.org/wiki/A_Symbolic_Analysis_of_Relay_a... (Claude E. Shannon) - basically lays out the equivalence of switching circuits to boolean algebra, fundamental to electronic computing

Note in fact many of Shannon's works and research could be considered "fundamental"...