If you use the update op you should be fine. The upsert would be in cases like “if it doesn’t exist, create a new one”. GraphQL spec doesn’t cover that. You have to manually set up such verification and probably do 2 operations, one to query and verify on your end, another the create or update.
Also, there’s no news about this as this was a question. Not a request. Usually, popular requests are prioritized on the backlog.