How to add a Schema derivation of a Union Type

I have a union type of 2 Scala 3 Enums, like

case class In(
      subStatusKey: SubStatusKeyDocuments | SubStatusKeyGeneral = SubStatusKeyDocuments.`documents-prepared`,
object In:
    given Schema[In] = Schema.derived
    given CirceCodec[In] = deriveCodec
end In

enum SubStatusKeyGeneral derives ConfiguredEnumCodec:
  case canceled
  case finished

object SubStatusKeyGeneral:
  given Schema[SubStatusKeyGeneral] = Schema.derived
end SubStatusKeyGeneral

This does not work - is there a working example or are union types not supported?
I use Circe for Json Marshalling.