The mistake you’re making is that determinism does not mean your decisions are irrelevant. The universe doesn’t swoop in and force you to decide a certain way even though you’d rather not. Determinism only means that your decisions, by being part of physical reality rather than existing outside it, result from the physical events that led to them. You aren’t free to make events happen without a cause, but you can still look at evidence and come to correct conclusions.
The mistake you’re making is that determinism does not mean your decisions are irrelevant. The universe doesn’t swoop in and force you to decide a certain way even though you’d rather not. Determinism only means that your decisions, by being part of physical reality rather than existing outside it, result from the physical events that led to them. You aren’t free to make events happen without a cause, but you can still look at evidence and come to correct conclusions.