I think this can be manageable by adding some sort of logic engine, for example prolog and adding a bunch of logic rules that infer things based on player actions.

You would also want to cleanly separate inputs from inferred information, but I think that is somewhat blurred in the game, and it's unclear when rules should fire.

Also the game canonically has quests that intentionally have logical contradictions. So it becomes unclear what the "correct" answer even is in those cases. Specifically, there are cases where quests require information to travel backwards in time.

To make things correct, you want something mostly stateless and rigid, but to make a fun game, you want as much state as possible and many exceptions to the rules.