I actually don't think any of this is relevant to the OP's situation, as by his own admission his interviews never progressed to any sort of production-level pr

I actually don't think any of this is relevant to the OP's situation, as by his own admission his interviews never progressed to any sort of production-level problems. He was just given algorithmic puzzles to solve. It sounds to me like the opposite of what you're saying: he's good at delivering to production, but he's not good at pet interview questions.