Xamarin.Forms - How to define scoped storage for android and how can I implement it to downlaod files in Downloads directory?

In my app I have given facility to download reports in PDF formats. Everything was good until I was testing my app on Android 10 and below. Recently I updated a device to Android 11 and now I am not able to download any file in shared storage. I am getting Access Denied error while downloading file.

I have given permission to read and write external storage

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

and my download path is

Android.OS.Environment.GetExternalStoragePublicDirectory(Android.OS.Environment.DirectoryDownloads).AbsolutePath;

I have also set android:requestLegacyExternalStorage="true" in AndroidManifest.xml

My code to download file looks like this

public async void DownloadSupplierSample(object sender, EventArgs e)
    {
        try
        {
            string basepath;
            if (Device.RuntimePlatform == Device.Android)
                basepath = DependencyService.Get<IDownloadPath>().GetDownloadsPath();
            else
                basepath = System.IO.Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Personal), "..", "Library");

            PermissionStatus readstatus = await Permissions.CheckStatusAsync<Permissions.StorageRead>();
            PermissionStatus writestatus = await Permissions.CheckStatusAsync<Permissions.StorageWrite>();

            if (readstatus == PermissionStatus.Granted && writestatus == PermissionStatus.Granted)
            {
                DownloadSupplier(basepath);
            }
            else
            {
                var read = await Permissions.RequestAsync<Permissions.StorageRead>();
                var write = await Permissions.RequestAsync<Permissions.StorageWrite>();

                if (read == PermissionStatus.Granted && write == PermissionStatus.Granted)
                {
                    DownloadSupplier(basepath);
                }
            }
            await DisplayAlert("", "Sample is downaloaded at Downloads directory","Ok");
        }
        catch (Exception ex)
        {
        }
    }

    async void DownloadSupplier(string basepath)
    {
        using (var stream = await FileSystem.OpenAppPackageFileAsync("SupplierMaster.xlsx"))
        {
            string filename = $"SupplierMaster_{DateTime.Now.ToString("yyyyMMddHHmmss")}.xlsx";
            string filepath = Path.Combine(basepath, filename);

            byte[] bytes = Utils.Common.StreamToBytes(stream);
            File.WriteAllBytes(filepath, bytes);
            //using (Stream filestream = File.Create(filepath))
            //{
            //    //stream.Seek(0, SeekOrigin.Begin);
            //    stream.CopyTo(filestream);
            //}
        }
    }

I have tried setting flag from device as well from this link

How can I define scoped storage for my app ?

Any update how can I download PDF file in my downloads directory ?

Thank you.

from Xamarin.Forms - How to define scoped storage for android and how can I implement it to downlaod files in Downloads directory?