You wrote “sometimes, I have to update the docker-compose.yml on the unit, or add a library, or change something outside of the unit.”

and “I am looking for something as simple as alembic, but obviously to run scripts not DB migrations.”

I don’t see how having to run scripts follows from the first. Can’t you put the stuff that lives outside docker images in a git repo and pull changes from that?

Initial install would be a git clone and updates a git pull (maybe with a reboot to make sure nothing is running that’s using outdated stuff)