This code using AVPlayer
works only on Playground
import AVFoundation
var player = AVPlayer()
let playerItem = AVPlayerIte
In SwiftUI, Views are value types. They are only data that describe the things on screen. They can be created or destroyed or copied at any time. AVPlayer is a reference to a specific player object. You're assuming here that it will continue to exist, and there will only be one of them. That's not something that a SwiftUI View provides.
You need to move your AVPlayer outside of the View (into Model objects), and just bind UI actions to it.