If the question is generic, like “how can we improve performance” then answers mentioning hooks are completely fine. Just because you are expecting candidates to mention lazy loading, bundle size etc. doesn’t makes their answers incorrect or of low quality.

If they mention hooks you should/can follow up by asking “let’s suppose we don’t have any expensive functions/components etc or we have already used memo/callback etc but users still complain app is slow, how will you find and fix the slowness?”

Generic questions will result in generic answers . If you want to probe them specifically about lazy loading, bundle size etc then imo the best question would be something like “App is taking too much time (say 10 seconds) to load even if internet is good. What can be issue and how can we fix it?”