To be honest, all I see is https://xkcd.com/927/
All config formats are bad. You either don't need all the features at all, except key:value. Or you quickly run into weird limitations and quirks.
What I rather like instead, are custom build english-like DSL's, like:
- https://man.openbsd.org/pf.conf - https://man.openbsd.org/smtpd.conf - https://man.openbsd.org/httpd.conf - … and many more
OpenBSD's daemons' configs are pleasant. But then you have to maintain a DSL for even small projects. Most people aren't going to want to implement and maintain a whole one-off config language for their small project. Which is why having a common, minimal option is nice.