How do you set the accent color of blur effect in user32.dll?

I am using the undocumented SetWindowCompositionAtribute API in user32.dll to make my windows form have a blur effect. This is the code I am using:

        public Form1()
        {
            InitializeComponent();
            this.EnableBlur();
            SetStyle(ControlStyles.UserPaint, true);
            SetStyle(ControlStyles.OptimizedDoubleBuffer, true);
            SetStyle(ControlStyles.SupportsTransparentBackColor, true);
            BackColor = Color.LimeGreen;
            TransparencyKey = Color.LimeGreen;


        } 
        //import dlls
        [DllImport("uxtheme.dll", EntryPoint = "#95")]
        public static extern uint GetImmersiveColorFromColorSetEx(uint dwImmersiveColorSet, uint dwImmersiveColorType, bool bIgnoreHighContrast, uint dwHighContrastCacheMode);
        [DllImport("uxtheme.dll", EntryPoint = "#96")]
        public static extern uint GetImmersiveColorTypeFromName(IntPtr pName);
        [DllImport("uxtheme.dll", EntryPoint = "#98")]
        public static extern int GetImmersiveUserColorSetPreference(bool bForceCheckRegistry, bool bSkipCheckOnFail);
        // Get theme color
        public Color GetThemeColor()
        {
            var colorSetEx = GetImmersiveColorFromColorSetEx(
             (uint)GetImmersiveUserColorSetPreference(false, false),
             GetImmersiveColorTypeFromName(Marshal.StringToHGlobalUni("ImmersiveStartSelectionBackground")),
             false, 0);

            var colour = Color.FromArgb((byte)((0xFF000000 & colorSetEx) >> 24), (byte)(0x000000FF & colorSetEx),
             (byte)((0x0000FF00 & colorSetEx) >> 8), (byte)((0x00FF0000 & colorSetEx) >> 16));

            return colour;
        }



        //Class to use user32.dll API
        public static class WindowExtension
    {
        [DllImport("user32.dll")]
        static internal extern int SetWindowCompositionAttribute(IntPtr hwnd, ref WindowCompositionAttributeData data);

        public static void EnableBlur(this Form @this)
        {
            var accent = new AccentPolicy();
            accent.AccentState = AccentState.ACCENT_ENABLE_BLURBEHIND;
            var accentStructSize = Marshal.SizeOf(accent);
            var accentPtr = Marshal.AllocHGlobal(accentStructSize);
            Marshal.StructureToPtr(accent, accentPtr, false);
            var Data = new WindowCompositionAttributeData();
            Data.Attribute = WindowCompositionAttribute.WCA_ACCENT_POLICY;
            Data.SizeOfData = accentStructSize;
            Data.Data = accentPtr;
            SetWindowCompositionAttribute(@this.Handle, ref Data);
            Marshal.FreeHGlobal(accentPtr);
        }

    }
    enum AccentState
    {

        ACCENT_DISABLED = 0,
        ACCENT_ENABLE_GRADIENT = 1,
        ACCENT_ENABLE_TRANSPARENTGRADIENT = 2,
        ACCENT_ENABLE_BLURBEHIND = 3,
        ACCENT_INVALID_STATE = 4,
        ACCENT_ENABLE_ACRYLICBLURBEHIND = 4,

    }

    struct AccentPolicy
    {
        public AccentState AccentState;
        public int AccentFlags;
        public int GradientColor;
        public int AnimationId;


    }

    struct WindowCompositionAttributeData
    {
        public WindowCompositionAttribute Attribute;
        public IntPtr Data;
        public int SizeOfData;
    }

    enum WindowCompositionAttribute
    {
        WCA_ACCENT_POLICY = 19,

    } 

Here is the effect:

I have tried changing AccentPolicy.GradientColor to 1, 2, 3, 4, 5 but the blur is still colorless. I want the blur on the Form to be the same as the accent color using my GetThemeColor() method

How do I do this?