I have deep knowledge of the underlying technologies, mostly deep knowledge of the languages. But my experience is that most interviewers do not care about this. They want to hear about your last project using their laundry list of libraries. Everyone wants me to assure them that I am a "React expert" or that I have "used AWS" and no one cares about the papers I've read recently or the first-principles, ground-up projects I've done. The only time anything approaching specialized knowledge comes up is when people ask trivia questions.

I think that's a concrete area for you to explore. When I hire, I'm often looking to hire to fill a specific skill gap on a project. I look for the specific skills I need right now and for skills I think will help the employee grow into other / more senior roles. But in the initial assessment I'm look for indications that the candidate can hit the ground running and be productive in a relatively short period of time. Of course sometimes I can't find the exact right candidate end-up broadening the filter. The learning for you here is to focus on selling you abilities in what the hirer is looking for. The rest are nice-to-haves.

I've got the same experience. It's weird how similar our experience in this interview process feels while we're literally years apart in work experience.