How do you identify researchers who are good? [D]

About 10 years ago, I got into the basics of ML (like regression, KNN’s, LVQ’s) and read a few papers before taking a break a few years back.

It feels like now, there’s a lot of researchers in AI. How do you identify the ones who are actually solid vs those who (forgive my phrasing) are more researchers for appearance/status (i.e don’t actually know what they’re talking about)?

Is the core filter h-index or where they work? How would you identify them?