Indeed, his philosophy on the nature of mathematics is closer to "discovery", as in physics, than "invention" as in arbitrary game of rules and symbols (Hilbert) or language game (Wittgenstein).

I forget who said, "If you keep asking why, eventually you end up in the mathematics department." Calling it Platonism is a misunderstanding of how physics (and chemistry, biology, and the rest) emerge from mathematical structures and relationships that are more fundamental.