POJOs and records require more configuration (e.g. Jackson's @JsonProperty, @JsonDeserialize). That could plausibly be out of scope.

But for constructing JSON out of strings, numbers, booleans, lists, and maps, there's really not that much scope to creep into.

Specifically, I think it would be perfectly cromulent to have JsonArray.of() be able to support any Iterable of native Strings, Integers, Doubles, or Booleans; that doesn't feel like feature creep to me at all. It would transparently support Sets. (Right now, the API only accepts Lists of JsonValues, which is what makes the API feel so ceremonious.)