Q:What if - and I’m aware how naive this may sound - what if consciousness IS a hidden variable, and every choice made has a physical manifestation in the form of a new particle that then deterministically acts upon the universe, physically altering the future.
A: Choices are conditions because everything is conditions, and all conditions including choices are conditioned by other conditions. Consciousness has nothing to do with choices tho. Computers also make choices. Consciousness is generally equated with either awareness, or self-awareness. So although computers make choices, they are not aware/conscious (supposedly) of having made choices. However, we have no way of proving that computers are less aware than we are, so it's just our assumption. However, if you take the phi (info feedback loop) measurement of consciousness seriously, then everything is aware to some degree, and computers will soon be more self-aware than us: https://www.hansonrobotics.com/tononi-phi-sentience-consciousness-and-smart-ai-futures/
Buddha explained in the Bahiya sutta that everything is awareness since awareness cannot be defined without some experience that's awared. In other words, there is no such thing as awareness since there's no opposite of awareness. Self-awareness, to Buddha, is merely a perversion of awareness in which reality is no longer directly experienced, but rather seen from a distance as an observer.
It is at the point that the illusion of unitary experience is dissolved that nibbana or unbound disjoint awareness is self-known without a knower, that it is realized that every energy flow/everything is aware without any concept of itself/existence.