There's HOCON which is pretty good if you can run on a JVM. It's a superset of JSON designed for readability and human-friendliness when writing config files. It doesn't change the type system and doesn't have yamls weird edge cases, but is still a lot easier to write than JSON. There's also a relatively tight spec.

https://github.com/lightbend/config/blob/main/HOCON.md

We use an extended version of it for our app and the resulting config is pretty clean. You can see an example here:

https://hydraulic.software/blog/8-packaging-electron-apps.ht...

The only downside is that the reference implementation is hardly maintained anymore.