Apple TV+ has a unified search (although Netflix doesn't participate), but something about the handoffs between APIs is painfully sloooow and the UX can get a little confusing if you're managing multiple user profiles (both at the Apple TV level and in each individual service) as well as getting very confused if you're able to access the same content through multiple services (e.g. HBO shows via Hulu or HBO Now).

It needs improvement fast. Ideally we'd decouple the technology/UX side of it from the content library management side of it but that'll never happen.