exactly what I was just discovering…
https://shopify.dev/docs/apps/build/graphql/migrate/new-product-model/add-data
“You can create up to 250 variants in a single batch using this mutation” nowhere at all does it state this is not yet deployed so I only discovered it today when trying to insert more than 100 to be faced with “Exceeded maximum number of variants allowed”
So yes it seems we have to wait 6+ months for Shopify to deploy the working code base to go with the public documentation.. This is a serious fail.