Because rebase is fraught with peril, if you also push rebased branches upstream and someone else works off that branch.
If you stick to the rule of only using rebase on local branches that have never been pushed upstream, it’s an awesome tool. If you don’t, you’re eventually going to cause someone to have a bad day.
I have a feeling you don’t quite understand what Docker is doing for you and how it works. I suggest looking for an intro to Docker and understand the basics around Docker volumes and networking in docker before trying to orchestrate a complex set of software in Docker.
Don’t give up! I was you about 6 years ago. I’m on my 3rd server setup now, and I’ve gone from where you are now, to being able to script my setup using Ansible and having those scripts versioned in Git, so I never have to worry about remembering how it’s all glued together.