This. Once you're building something that genuinely hasn't been built before, LLMs cannot be trusted with any architectural decisions. I'm building a product based around various physics simulations, so it's purely first principles, but without active research, thinking, and challenging, it produces computational code literally hundreds of orders of magnitude slower WHILE implementing absurd fallbacks and shortcuts that effectively result in a useless calculation.

This is the case perhaps 95% of the time.

Oversight is very important, and architectural thinking cannot yet be outsourced, only execution.