Resizing a window with Windows API in C#

Question

I am trying to launch a program ("notepad.exe" for example) and then resize the window. When I run the code below I get a non-zero window handle but setWindowPos does nothing (it does not throw an error). Can someone help me understand what i am doing wrong, I am new to the Windows API.

[DllImport("user32.dll", EntryPoint = "SetWindowPos")]
public static extern IntPtr SetWindowPos(IntPtr hWnd, int hWndInsertAfter, int x, int Y, int cx, int cy, int wFlags);
static void Main(string[] args)
{

    try
    {
        // Start the process
        Process process = new Process();
        process.StartInfo.FileName = "notepad.exe";
        process.Start();

        process.WaitForInputIdle(2000);

        // Get the process handle
        IntPtr processHandle = process.Handle;
        if (processHandle == IntPtr.Zero)
        {
            Console.WriteLine("Null pointer");
        }

        Console.WriteLine($"Process started with handle: 0x{processHandle.ToInt64():X}");
        try
        {
            // 0x0040 is SHOWWINDOW

            SetWindowPos(processHandle, 0, 0, 0, 1000, 200, 0x0040);
            Console.WriteLine("Set the window position");
        } catch (Exception e)
        {
            Console.WriteLine(e);
        }
        Console.ReadLine(); // Keep handle valid until user input
    }
    catch (Exception ex)
    {
        Console.WriteLine($"Error: {ex.Message}");
    }
}