`psych`, used for YAML, is a different thing than Marshal. pstore uses Marshal.
https://ruby-doc.org/core-2.6.3/Marshal.html. I don't believe psych will be involved with pstore.
I'm honestly not sure, though, how much I should be worried about the fact that someone who has write access to my database can maybe escalate that to an arbitrary code execution if I use pstore. Literally not sure. Write access to my DB seems pretty disastrous already...