While this thread isn’t aimed specifically at what you’re doing (it covers alternative iOS 🡘 macOS sync methods), it does dip into how to recover from mistakes in a way that is very easy and safe to use—because in fact we are using a tool that was designed to make collaboration easy.
Or in other words, there is already a mechanism in Scrivener that lets you edit a project concurrently, between any arbitrary number of sessions and over any time scale, and safely merge the variations together into one master copy again.
I should stress, and remind, that the wording in that post is aimed at iOS syncing, and is couched within the notion of using another approach to syncing entirely—but that approach is not necessary for this to be available as an option. You get this option by the very action of creating a copy of the project to edit safely. The other method creates copies by virtue of the automatic backup system. One is deliberate, the other is ad hoc, but in the end they both have the same result.
Note there is also the General: Automatic Quit, settings pane. I don’t like to recommend that as an actual workflow though, because then you have to waste electricity leaving all of your devices on all of the time. It should be better thought of as a failsafe that might help you out, but most often if you forget you’re going to have to clone a copy and merge it later (which again, is so painless because it’s meant to be a workflow not a recovery feature).