Quick example, Hiring a mobile developer: You talk with them, if Android, ask how Kotlin interfaces with the JVM and what they think (good or bad) about type erasure. iOS? Ask/talk a bit about memory management/ARC. Anyone that has experience with these languages/os (unless hiring for very junior position) should have some thoughts and opinions about it. They may say something you don't agree with (ARC is crap because X or Y) but they will know what they are talking about. You can also dig in to know if it is something they read online (ARC is automated reference counting, meaning each 'allocation' increases a ref counter. Ok, that is good, so, why use `autorelease` or `release` and when to use each? etc etc kind of questions)
You can do the same with backend (framework vs libraries) or frontend (react + state libraries) or whatnot, but if in an one hour tech chat with someone, you can't understand if they actually know they can at least code similar to giving them a fizzbuzz or whatnot, it says more about the interviewer than the person being interviewed.