How to hide cursor and disable mouse click?

I'm trying to create menus in my game where I can choose options by the arrows keys on the keyboard so I don't want the mouse cursor to appear at all. I don't want to hide it only, I want to disable mouse clicks for the entire game too. Currently, I have created a Pause Menu with multiple options that I can choose from using the keyboard arrow keys, However, when I click using the mouse anywhere on the screen the buttons on the menu lose focus and I can't choose from the menu anymore. How can I fix this?

Here is my code for the PauseMenu:

 public static bool GameIsPaused = false;
     public GameObject pauseMenuUI;
     // Update is called once per frame
     void Update()
     {
         if (Input.GetKeyDown(KeyCode.Escape))
         {
             if (GameIsPaused)
             {
                 Resume();
             }
             else
             {
                 Cursor.lockState = CursorLockMode.Locked;
                 Cursor.visible = false;
                 Pause();
             }
         }
     }
     public void Resume()
     {
         pauseMenuUI.SetActive(false);
         Time.timeScale = 1f;
         GameIsPaused = false; 
     }
     private void Pause()
     {
         pauseMenuUI.SetActive(true);
         Time.timeScale = 0f;
         GameIsPaused = true;
     }

the cursor sometimes still appear and even when it is hidden I can still click on the screen and once I click on the screen the menu options get unselected and I can't choose an option anymore. How can I fix this??