[...][datastore] however, is still part of s-abstractions (it saves a single state to a subpatch), and it doesn't work here. I tried datastore-help.pd and it saves an empty state. What's interesting, is that if I try it while my other big patch is open, it consistently triggers a segfault.
Without seeing your patch this conversation is unfortunately entirely pointless.
It could be that you're using a third-party external that somehow trips up and crashes when a pest I'd invoked, fails, and outputs bogus data that makes the external crash and that is something that I cannot even begin to backtrace without knowing exactly what crashed. It could be also that you are as you're suggesting mixing two different versions of preset abstractions which itself appears to be causing some of the problems you're encountering and the list goes on. To begin, you could provide a backtrace of the consistent crash so that we have some idea of what is going on.