Why is the GraphQL admin translations API not delivering as expected?

Technical Q&A
1

The translation api seems broken in many ways:

getting translation from a product works:

query {
  product(id: "gid://shopify/Product/XXXX") {
    id
    translations(locale: "fr") {
      key
      locale
      value
    }
  }
}

getting the same translations from the translatableResource query gives nothing:

query {
  translatableResource(resourceId: "gid://shopify/Product/XXXX") {
    translatableContent {
      key
      locale
      value
      digest
    }
    translations(locale: "fr") {
      key
      locale
      value
    }
  }
}

Also, the documentation clearly says that “you can query translations directly from a translatable resource object”. Yet the Metafield type has no translations field, but is a valid TranslatableResourceType.

And this is only a small subset of the issues i encoutered. How are we supposed to work with this API when half the functionalities are (silently) not implemented?