I'm surprised there's no widely-adopted library for general-purpose languages that handles user-friendly object input and outputs static config (perhaps in JSON

I'm surprised there's no widely-adopted library for general-purpose languages that handles user-friendly object input and outputs static config (perhaps in JSON) for machines to read. Instead, there are several DSLs that act as dynamic config, and even some that generate dynamic config, or something in the middle like k8s YAMLs. Have I just not thought hard enough about this problem yet, and a DSL is really needed for it? Or should I go write that lib?