Creating a shortcut to press a button in an app???

I would like to create a shortcut that opens my garage door when I say “Open sesame!”. I’ve gotten as far as opening the third party app that connects to the device that triggers the garage door opener.. but that’s where I’m stumped. The third party app is very simple.. it just displays a giant purple button. Is there an action that will press that button? It seems as if there should be. A press is just a contact with the screen recorded at specific coordinates, so is there a way to tell the phone that the screen has been touched at x, y? Or is this one of those things that’s just not possible?