I also own The Witcher 3 through Origin and can still access the existing game in the EA App without any problems.
My issue is only the new free Remastered upgrade, which currently appears to exclude Origin / EA App owners.
I contacted EA Support. After several replies and some misunderstandings, they confirmed that Customer Support cannot really resolve this and that my feedback would be submitted for review. They also recommended supporting relevant threads here in the forum.
In parallel, I have contacted CD Projekt RED Support as well, but I have not received a response yet.
The main question remains: what happens to customers who legitimately bought The Witcher 3 through Origin when other PC owners receive the Remastered upgrade for free?
If EA no longer distributes the Remastered version, there should be some migration, redemption or transfer option for existing Origin customers.