Ask HN: Automate Changes in Multiple Projects

I have some containers running and part of them are based in the first project, let's call it "Server1".

Since there was no planning (these are my personal projects), Server2, Server3 and Server4, are basically copy/paste from Server1 with a few changes in the code. This leads to me having multiple Dockerfile and other files, being duplicated among the projects with minor changes according to the project itself.

This weekend I've updated Server1 with a new Docker image and fixed a bug in one of the bash scripts used by the app, since it worked as expected, I had to manually replicate the changes on Server2, 3, 4 and so on...

Building and deployment are automated, no problem with this, I'm using Gitea Actions & Portainer hooks, however, I would like to hear some suggestions on how to automate this manual labor also, not only the Dockerfile itself, but also the bash scripts, etc, basically, all those common files that all the apps share.

Thank you.