for those who is migrating your account from device A to B, create 1extra gmail acc other than the 1 in your destination device. lets say your original firstname.lastname@example.org, create an extra acc email@example.com, use this acc in your destination device and create a gods acc, because later on, u have to login this spare acc to switch to your old acc.
for those who is unsure about how to add acc in google device
1)go to settings in the account you want to migrate,
2)you will see a bind option beside igg id, after bind, it will change to switch
3)after bind successful, exit gods, go to destination device, launch gods Rush, settings, click the switch option beside igg id, firstname.lastname@example.org(your original acc), game will auto exit, relaunch Gods rush, and your original is now on your destination device.