In SSIS, i have a “Data Flow”, which contains “OLE DB Source” and Flat File Destination (CSV).
The Original CSV is also UTF-8:

The Flat file is UTF8:

When I Run it, data transfers correctly from SQL server to Excel file.
But there will be 1 empty line as the last line.
I wrote a c# script in “script task editor” , to remove the last empty line.
It also works correct BUT It changes the German alphabet (ä, ö, ü, ß):

Although i wrote in C# about keeping UTF8 format:

  using (var reader = new StreamReader(sourceFile, Encoding.UTF8))
  using (var writer = new StreamWriter(tempFile, false, new UTF8Encoding(true))) 

Does anyone know what is the problem with this C# code that it leads to change German alphabets?

 public void Main()
    {
        try
        {
            // Retrieve the file path from the SSIS variable
            string sourceFile = Dts.Variables["User::SourceFilePath"].Value.ToString();
            string tempFile = Path.GetTempFileName();

            // Use UTF-8 encoding for both reading and writing
            using (var reader = new StreamReader(sourceFile, Encoding.UTF8))
            using (var writer = new StreamWriter(tempFile, false, new UTF8Encoding(true)))
            {
                string line;
                bool isFirstLine = true;
                // Read each line from the source file
                while ((line = reader.ReadLine()) != null)
                {
                    // Check if the line is not empty or whitespace
                    if (!string.IsNullOrWhiteSpace(line))
                    {
                        // Write the non-empty line to the temp file
                        if (isFirstLine)
                        {
                            writer.Write(line);
                            isFirstLine = false;
                        }
                        else
                        {
                            writer.Write(Environment.NewLine + line);
                        }
                    }
                }
            }

            // Delete the original source file
            File.Delete(sourceFile);
            // Rename the temp file to the original source file name
            File.Move(tempFile, sourceFile);

            // Indicate successful execution
            Dts.TaskResult = (int)ScriptResults.Success;
        }

In Connection manager, Code Page is: 65001 (UTF-8)
Locale: German