Inject JS code into cefsharp(inject youtube iframe)

I looked into lots of writing so I thought the code that I wrote should be working as well but it doesn’t. So I need help with finding out what is wrong with my code.

    private void Music_Control_JS(object sender, FrameLoadEndEventArgs e)
    {
        if (e.Frame.IsMain)
        {
            string url = e.Frame.Url;

            if (url.Contains("?autoplay=1"))
            {
                music_player.ExecuteScriptAsync(@"
                var tag = document.createElement('script');
                tag.src = 'https://www.youtube.com/iframe_api';
            ");
                music_player.ShowDevTools();
            }
        }
    }

so what I’m trying to do here is whenever music is played(“autoplay=1”) cefsharp will be loaded with youtube video and automatically play but in the meanwhile, I want to inject js code in to html. But it seems like it is not working. I check js is not injected using showdevtools.

what I’m trying to do using iframe api is to control youtube video using c# component(button, slider, etc)