This post shows you how to Disable Maximize Button for Console Window in C#. You can use Win32 API to disable maximize and minimize buttons for c# console application as shown below.

private const int MF_BYCOMMAND = 0x00000000;
public const int SC_CLOSE = 0xF060;
public const int SC_MINIMIZE = 0xF020;
public const int SC_MAXIMIZE = 0xF030;

public static extern int DeleteMenu(IntPtr hMenu, int nPosition, int wFlags);

private static extern IntPtr GetSystemMenu(IntPtr hWnd, bool bRevert);

[DllImport("kernel32.dll", ExactSpelling = true)]
private static extern IntPtr GetConsoleWindow();

You just need to call the DeleteMenu method from the Main thread to disable maximize button for console window application.

static void Main(string[] args)
    DeleteMenu(GetSystemMenu(GetConsoleWindow(), false), SC_CLOSE, MF_BYCOMMAND);
    DeleteMenu(GetSystemMenu(GetConsoleWindow(), false), SC_MINIMIZE, MF_BYCOMMAND);
    DeleteMenu(GetSystemMenu(GetConsoleWindow(), false), SC_MAXIMIZE, MF_BYCOMMAND);