Indeed, and if it stops working, debugging the wire will be much easier than reverse-engineering an obsolete mobile application.

If you need wireless and are not adverse to some tinkering, a pair of Arduinos, a button, a buzzer and a pair of RF 433MHz transceivers [1] may do the trick!

[1] https://randomnerdtutorials.com/rf-433mhz-transmitter-receiv...

Rather than trying to add a button at the front door, tap into your existing buzzer (or listen to it, maybe with an accelerometer on the Arduino)

I use the live feed from the Reaper drone overhead.