You're right - the Bill Gates injecting nano-particles into COVID vaccine has its basis in several pre-existing conspiracy theories, such as anti-vaxx, fears of RFID/"Mark of the Beast" tagging, Satanic/ritualistic activities by elites (see: Bohemian Grove, Skull and Bones, etc.) which themselves are derived from (albeit not always directly indicative of) anti-Semitic conspiracies.

Even with QAnon, the pieces were already there among the right-wing and extremist Christianity, they were just assembled into a single, somewhat coherent narrative.