I came across https://kdl.dev recently, and it has become my favored yaml-replacement when normal code doesn't work.

The data model is closer to XML than JSON, though, so unfortunately it's not a drop-in replacement for yaml.

Small sample:

  package { 
    name my-pkg 
    version "1.2.3"
    dependencies { 
      // Nodes can have standalone values as well as // key/value pairs. 
      lodash "^3.2.1" optional=#true alias=underscore 
    }
 }

I wish they had some sort of include/composable file mechanism though