If you are willing to use private APIs and want a little bit more control you can set a private delegate on AVPlayerViewController. The delegate provides some special callbacks which among other things allow you to disable pause completely.
@objc protocol YourPrivateAVPlayerViewControllerDelegate {
@objc optional func playerViewController(_ controller: AVPlayerViewController, shouldPlayFromTime: TimeInterval, completion: @escaping (Bool) -> Void)
@objc optional func playerViewController(_ controller: AVPlayerViewController, shouldPauseWithCompletion: @escaping (Bool) -> Void)
}
You could implement the second delegate method and call shouldPauseWithCompletion(false) to disable pause. If you want to disable pause depending on the type of stream or some other properties you could do that as well of course.
Set the delegate implementation on the AVPlayerViewController with:
playerController.perform(Selector(("setPrivateDelegate:")), with: self)