My version really relies on how much her father hates Exegol. He could have PTSD after all the crazy experiments they put him through.

The first thing I want Ochi to tell them is that he’s taking them to Exegol and they’re never going to be able to leave.

So he has two choices: tell Ochi where Rey is and go back to the living hell that is Exegol to him, or keep that to himself and just end the misery. I agree that they would rather keep on living than spite Palpatine, but that’s exactly why I added in what I just said. He doesn’t want to suffer as a guinea pig anymore and would rather die.