Hi Chuck,
usually, you should do the following:
Make relevant changes in the admin only in the prod version and sync
them to your dev version when needed. Here, syncing includes the
database as a whole and the whole MEDIA_ROOT folder.
Make changes to your code only on your dev version and sync them to
the prod version, preferably using git. Here, syncing includes your
code, the required python packages, and database migrations. It
might require a collectstatic command, or a server process restart.
I don't know a reliable approach that merges two versions of your
database.
Best
Philipp