Have you seen tmuxinator basically does same and also as screen background app. https://collectiveidea.com/blog/archives/2017/03/27/using-tmuxinator-to-automate-your-environment

Syntax wise it so similar, few keywords here and there. I will keep on eye on mert. Here my config example. It is vim for editor, rails api only and standard frontend. https://gist.github.com/mrancys/316ea7f91a0036aff170f67c4c5f1bbc