Seth Anil has interesting lectures on consciousness, specifically on the predictive processing theory. Under this view the brain essentially simulates reality as a sort of prediction, this simulated model is what we, subjectively, then perceive as consciousness.

“Every good regulator of a system must be a model of that system“. In other words consciousness might exist because to regulate our bodies and execute different actions we must have an internal model of ourselves as well as ourselves in the world.

As for determinism - the idea of libertarian free will is not really seriously entertained by philosophy these days. The main question is if there is any inkling of free will to cling to (compatibilism), but, generally, it is more likely than not that our consciousness is deterministic.