We've been trying to get support for this (and clarification in the docs) since it was released 5 years ago in 2021 (tvOS 15). What is the correct avenue for that? So far we've tried Feedbacks, DTS Tickets and WWDC chats to get clarity on this and get some progress. Is there something else we should do?

By "availability information" do you mean the documentation? The APIs themselves seem to have incorrect availability information, as it lets us compile with APIs that you are saying are not available on those platforms.

So when the documentation says it supports: iOS 15.0+ iPadOS 15.0+ Mac Catalyst 15.0+ macOS 12.0+ tvOS 15.0+ visionOS 1.0+ it's just not accurate? https://developer.apple.com/documentation/avkit/avpictureinpicturecontroller/contentsource-swift.class/init(samplebufferdisplaylayer:playbackdelegate:) https://developer.apple.com/documentation/avkit/avpictureinpicturesamplebufferplaybackdelegate