Go to your phone files,
Android > data > you will find a file with the game name...
Rename it to something else,then uninstall the game.
Then after downloading the new version from play store, before opening the app, go rename the file that you renamed earlier to its original name.
Thats all...now you will find your progress saved..
that trick don't work for most games happy to see it works on this one. The video in the main topic, only shows few files to be copied though not the entire game folder. did you try that method?
btw what's endless bank? is it the capacity of the chest in the town?
and what's stealing?