It seems that PDFPageOverlayViewProvider is set in the UIViewRepresentable of PDFView derived from class Coordiantor: NSObject. I wander why Apple doesn’t provide the demo App presented in the video. Maybe, the protocol is not working yet in the beta version.

Nope. I wander if it is possible to roll back to iOS / iPadOS beta 5, but I do not know where to download beta 5 ipsw.