Isn't it possible to make all these changes in a server and make it available as a docker container or VM (with minimal customization required for end users?)
For sure! After years of running a personal mail server with a setup similar to what's described in the article, I moved to using a pre-built docker setup and haven't looked back: https://github.com/tomav/docker-mailserver
The easiest way to get this type of VM setup going is to start up the container on your mail host with all of the fun features (filters mostly) turned off, verify that the new mail container works as expected, then slowly start turning on features one by one so that if you happen to break something with a bad configuration you know how to roll back to a configuration that is functional.
