How to get remote volume buttons to work on airplay(TVOS)?

Hello,
I am setting up a simple test app on TVOS to airplay the audio of a video to a Apple HomePod. The audio plays great but it seem that I cannot control the volume using the TVOS remote. I would assume that would work right out of the box but it does not.
So the question is am I supposed to create something or do something with `AVAudioSession`?
Note: I am not using AVPlayerViewController(which using this works). I am using AVPlayerLayer.
Audio Session Setup(AppDelegate.m

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    // Override point for customization after application launch.
    
    AVAudioSession* audioSession = [AVAudioSession sharedInstance];
    [audioSession setCategory:AVAudioSessionCategoryPlayback mode:AVAudioSessionModeMoviePlayback routeSharingPolicy:AVAudioSessionRouteSharingPolicyLongForm options:0 error:nil];
    [audioSession setActive:YES error:nil];
    return YES;
}

Player Creation(ViewController.m)

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    NSString *assetURI = @"https://bitdash-a.akamaihd.net/content/MI201109210084_1/m3u8s/f08e80da-bf1d-4e3d-8899-f0f6155f6efa.m3u8";
    NSURL *urlRequest = [[NSURL alloc] initWithString:assetURI];
    // Create an AVPlayer, passing it the HTTP Live Streaming URL.
    _player =  [AVPlayer playerWithURL:urlRequest];
    
    // Has to be set `NO` for audio of the video to airplay.
    _player.allowsExternalPlayback = NO;
    
    _playerLayer = [AVPlayerLayer playerLayerWithPlayer:_player];
    _playerLayer.videoGravity = AVLayerVideoGravityResize;
    
    // Provide a way to select route
    AVRoutePickerView* view = [[AVRoutePickerView alloc] initWithFrame:CGRectMake(0, 0, 100, 100)];
    
    [self.view.layer addSublayer:_playerLayer];
    [self.view addSubview:view];
}

Any suggestion would be apretiated.
Thanks in advance!