I've gotten into the habit of creating project.kdl files in project root directories. Then, it's a matter of running zellij --layout project.kdl to launch everything I need to hack on something. It is somewhat unnecessary; most of the time Zellij stays open, but I like it.

To do it, you can set up your Zellij layout as you like, and then run zellij action dump-layout > project.kdl to creata layout.