Single-player game on Multiple Screens?

I would like to be able to do something like this. Except I want a 4th screen that will be below the 3 main screens. This 4th screen will be used just to display an interactive widget, and the 4th screen will most likely be a smaller screen than the other 3. I know I can have the game viewport display on the 3 main screens by using borderless windowed mode, but I’m having difficulty figuring out a good solution for the 4th screen. Based on my research, one solution is to create a networked game and have two clients running. The first client would be displayed on the 3 main screens while the 2nd is just on the 4th screen. This seems like it would work but is less than an ideal solution for my setup.

Another solution I came across was the code in this post. I’m slightly hesitant to try this method as the poster of the code doesn’t seem very confident in their method. Does anyone more knowledgeable than me think this is what I need?

Any help is appreciated.