The experience factor is huge here, and should be pinpointed. Being able to work in a non-academic environment is incredibly important, because honestly the pace and quality of technical work done in academic settings just isn't comparable.

> "Companies hesitated to hire a Ph.D. with no industry experience"

That, for me, would be the #1 red flag. How does one even go through getting a PhD without getting any industrial experience? Not a single internship, even as an undergraduate?

This tells me that either the PhD literally can't code (and hence nobody even wanted them as an intern) or despises industry so much that they never wanted an internship (and hence I'd be pretty worried about how much they'd be committed to the new job).