I used to do this when on Windows too: C was for the OS and apps, D was for user data. The same principle here - separating OS from data is a game changer - and even easier on Linux I think. Makes it so easy to wipe a partition and try something new.
Just pass in the name of a json file as a CLI input (or default the name and act on it if present or use it if indicated [e.g. /U == use json.config]).