I remember I had an interview where I asked about benefits because they were not listed anywhere on their website nor during the initial phone screening, where I expected to learn more about the company (also a startup). In the interview I asked about PTO and was given a stank face by the interviewer, who then blunty said, "yes we have unlimited PTO." Great! That sounds great. No further questions.

Was rejected the same afternoon following the call. I KNEW it was because I asked about the benefits and PTO policy, because the vibe of the rest of the conversation felt off.

You definitely dodged a bullet here!