AVPlayerViewController buttons

I have an app which plays a series of videos for the user, with optional looping of the series. My view has an AVPlayerViewController attached to it, and I initiate and control playback by passing an array of items to these two functions:

     private func play(_ items: [Item], loopAll: Bool) throws {
        let player = AVQueuePlayer()
        playerController = AVPlayerViewController()
        playerController!.player = player
        self.present(playerController!, animated: true) {
            for item in items {
                self.addItemToQueue(player: player, item: item, loopAll: loopAll)
            }
            player.actionAtItemEnd = .advance
            player.play()
        }
    }
   
    private func addItemToQueue(player: AVQueuePlayer, item: Item, loopAll: Bool) {
        let playerItem = AVPlayerItem(url: item.videoUrl)
        player.insert(playerItem, after: player.items().last)
        NotificationCenter.default.addObserver(forName: NSNotification.Name.AVPlayerItemDidPlayToEndTime, object: playerItem, queue: nil) {
            note in
            if (loopAll) {
                self.addItemToQueue(player: player, item: item, loopAll: loopAll)
            }
        }
    }

This works great, with the exception of the forward/back buttons in the AVPlayerViewController. Play/Pause, Done, and scrubbing work as expected, but tapping either Forward or Back has no effect. How can I enable those buttons to actually call player.advanceToNextItem, or worst case, hide them so the user doesn't see confusing/useless buttons during playback?