Tell HN: Cure for imposter syndrome

Tell your new Jr hires it is normal. It is normal for anyone to not know a brand new codebase. Even the most experienced programmer will need an acceptable amount of time before being acquainted with a codebase and architecture. They only know how to ask better questions.

So teach your new hires and guide them towards the right question.

It is not up to the new hires to get our of the imposter syndrome. It's most likely because you are making them feel that way, asking for the impossible.