[GoblinSlayer]

>especially with how easily theories of predeterminism tend to enable unproductive, nihilistic outlooks

That's an essential claim, not doubt. First, you're wrong that determinism is a synonym for predeterminism, science doesn't support it, because predeterminism contradicts the second law of thermodynamics. Next you're wrong that nihilism is bad. Is it a dogma? What if you're wrong? Especially since you know yourself your knowledge about nihilism is fragmentary and you spent only microscopic amount of effort to understand it and can't make grand conclusions about it. Then you also imply that delusion is somehow more constructive than truth. That's counterintuitive and needs proofs.