You would do well to learn by past and current attempts. This book should be enlightenig (and yes, Elektra is very much alive): https://www.libelektra.org/ftp/elektra/publications/raab2017...
Would also be a useful excercice to write a new configuration UI for existing configuration backend(s) (preferably something already in use by some software you're already in want of better configuration for) - even if you do end up aiming at your own standard (xkcd.com/927), it should give you some clarity on ways to approach it.