Window opacity not being effected in a method?

<Window x:Class="NAME.overlay"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:NAME"
        mc:Ignorable="d"
        Title="overlay" Height="450" Width="800" WindowState="Maximized" WindowStyle="None" Topmost="True" AllowsTransparency="True" Opacity="{Binding WindowOpacity}" Visibility="Hidden">
</Window>

<Window x:Class="NAME.overlay"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:NAME"
        mc:Ignorable="d"
        Title="overlay" Height="450" Width="800" WindowState="Maximized" WindowStyle="None" Topmost="True" AllowsTransparency="True" Opacity="{Binding WindowOpacity}" Visibility="Hidden">
</Window>

        public overlay()
        {
            InitializeComponent();
            this.Loaded += Overlay_Loaded;
            WindowOpacity = 0.2;
            DataContext = this;
        }

        public overlay()
        {
            InitializeComponent();
            this.Loaded += Overlay_Loaded;
            WindowOpacity = 0.2;
            DataContext = this;
        }

        public void SetOpacity(overlay window) // Function is ran outside of this class
        {
            window.WindowOpacity = 1; // This doesn't work
            Trace.WriteLine("Works"); // This prints
        }

        public void SetOpacity(overlay window) // Function is ran outside of this class
        {
            window.WindowOpacity = 1; // This doesn't work
            Trace.WriteLine("Works"); // This prints
        }

        public void CSGOFlash() // Function is ran outside of this class
        {
            WindowOpacity = 1; // This doesn't work
            Opacity = 1; // or this :(
            WindowState = WindowState.Normal;  // This works????
            Trace.WriteLine("Works"); // This prints
        }

        public void CSGOFlash() // Function is ran outside of this class
        {
            WindowOpacity = 1; // This doesn't work
            Opacity = 1; // or this :(
            WindowState = WindowState.Normal;  // This works????
            Trace.WriteLine("Works"); // This prints
        }

    public partial class App : Application
    {
        protected unsafe override void OnStartup(StartupEventArgs e)
        {
            const long WS_EX_COMPOSITED = 0x02000000L;
            const long WS_EX_TRANSPARENT = 0x00000020L;


            overlay window = new();
            window.Show();
            IntPtr windowHandle = new WindowInteropHelper(window).Handle;

            nint currentStyles = User32.GetWindowLongPtr_IntPtr(windowHandle, User32.WindowLongIndexFlags.GWL_EXSTYLE);
            if (currentStyles == 0) throw new Win32Exception();

            nint result = (nint)User32.SetWindowLongPtr(windowHandle, User32.WindowLongIndexFlags.GWL_EXSTYLE, (void*)(currentStyles | WS_EX_COMPOSITED | WS_EX_TRANSPARENT));
            if (result == 0) throw new Win32Exception();

            base.OnStartup(e);
        }

    }
}

    public partial class App : Application
    {
        protected unsafe override void OnStartup(StartupEventArgs e)
        {
            const long WS_EX_COMPOSITED = 0x02000000L;
            const long WS_EX_TRANSPARENT = 0x00000020L;


            overlay window = new();
            window.Show();
            IntPtr windowHandle = new WindowInteropHelper(window).Handle;

            nint currentStyles = User32.GetWindowLongPtr_IntPtr(windowHandle, User32.WindowLongIndexFlags.GWL_EXSTYLE);
            if (currentStyles == 0) throw new Win32Exception();

            nint result = (nint)User32.SetWindowLongPtr(windowHandle, User32.WindowLongIndexFlags.GWL_EXSTYLE, (void*)(currentStyles | WS_EX_COMPOSITED | WS_EX_TRANSPARENT));
            if (result == 0) throw new Win32Exception();

            base.OnStartup(e);
        }

    }
}

HWND hwnd = CreateWindowEx(
    0,                              // Optional window styles.
    CLASS_NAME,                     // Window class
    L"Learn to Program Windows",    // Window text
    WS_OVERLAPPEDWINDOW,            // Window style

    // Size and position
    CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT,

    NULL,       // Parent window    
    NULL,       // Menu
    hInstance,  // Instance handle
    NULL        // Additional application data
    );

if (hwnd == NULL)
{
    return 0;
}

HWND hwnd = CreateWindowEx(
    0,                              // Optional window styles.
    CLASS_NAME,                     // Window class
    L"Learn to Program Windows",    // Window text
    WS_OVERLAPPEDWINDOW,            // Window style

    // Size and position
    CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT,

    NULL,       // Parent window    
    NULL,       // Menu
    hInstance,  // Instance handle
    NULL        // Additional application data
    );

if (hwnd == NULL)
{
    return 0;
}

HWND hwnd = CreateWindowEx(
    0,                              // Optional window styles.
    CLASS_NAME,                     // Window class
    L"Learn to Program Windows",    // Window text
    WS_OVERLAPPEDWINDOW,            // Window style

    // Size and position
    CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT,

    NULL,       // Parent window    
    NULL,       // Menu
    hInstance,  // Instance handle
    NULL        // Additional application data
    );

if (hwnd == NULL)
{
    return 0;
}

HWND hwnd = CreateWindowEx(
    0,                              // Optional window styles.
    CLASS_NAME,                     // Window class
    L"Learn to Program Windows",    // Window text
    WS_OVERLAPPEDWINDOW,            // Window style

    // Size and position
    CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT,

    NULL,       // Parent window    
    NULL,       // Menu
    hInstance,  // Instance handle
    NULL        // Additional application data
    );

if (hwnd == NULL)
{
    return 0;
}