I tried out a new phone the other day and part of the set up process allowed me to connect my old phone to my new phone with a USB cable and basically copy across apps and other data. At the end of the process I had the same identical setup on the new phone as I had on the old phone. Including the cellnuvo app was copied exactly and active on both devices. I confirmed the app credited silver on both to the same account.
The new phone was a pixel and the old a nexus. Not sure if this was a pixel feature. Both also had usb-C so I was able to connect both together using a usb-c to usb-c cable.
I sold the pixel in the end (not worth the money!) but I had the app crediting silver on two devices for a while. Not sure if cellnuvo fraud protection will block something like this so attempt at your own risk.