+1 for the above... all my apps are under /app/appname/(compose and data)... my backup is an rsync script that runs regularly... when I've migrated, I'll compose down, then rsync then rsync to the new server, then compose up... update dns, etc.

It's been a pretty smooth process. No, it's not a multi-region k8s cluster with auto everything.. but you can go a long way with docker-compose files that are well worth it.