One might argue that Newton didn't use any technique to invent calculus, just a very high IQ or some other unusual set of biological traits.

That would be a non-explanation in any case. However high Newton's IQ may have been, his brain was still operating by lawful processes within the physical universe. By the sheer improbability of inventing calculus by chance, there is bound to exist some general technique used by Newton for doing things like inventing calculus, for all that that technique may have been opaque to Newton's own conscious introspection. Perhaps someone else may be able to formulate this technique in explicit generality (in the same way that Newton himself formulated the methods of calculus, already known in special cases, in explicit generality).

"High IQ" probably doesn't mean more than something like high processing speed and copious amounts of RAM. The algorithms (at least in their essence) can still be run, less efficiently, on inferior hardware.