You could try Project My Screen App. With the app you can use the phone externally by connecting it to PC via USB cable. The only problem is that using the application requires allowing the screen projection on the phones’s screen so
I think the method won’t unfortunately work in your case where the screen is completely out of game.
I’ve used the app once with Lumia 625 whose screen was that broken that it showed the whole display image but didn’t respond to touch so I couldn’t really use the phone. I decided to use the Project My Screen App to access the phone again. So the problem for me, too, was how to press OK on that confirmation message on the broken screen. Very luckily I managed to press the confirmation button as some small parts of the touchscreen worked.
I’m not sure, though, if it’s somehow possible to bypass the confirmation, so you can try it anyway. Hopefully somebody has a better answer to your question.
P.S. I am new to this community too so this answer perhaps doesn't fit the rules either.