I just figured the way to access to data folder and the way to continue the game with the old data without having to start a new. Please read the following instructions first before proceeding to install your game.
1. You need to download a file explorer app. (Default file explorer app seems to not be able to access to the data files. However, if your default file explorer app can access to data files then no need to download any extra app)
https://play.google.com/store/apps/details?id=com.lonelycatgames.Xplore
(My device is working with Android 11. The app from the following link will help you to access to those data files.)
2. Find the data files of this game using the file explorer app of your choice.
*The data folder of Tavern of Spear name is "tavern.of.spear"*
3. COPY the "files" folder then paste somewhere else that's not in "tavern.of.spear" folder
4. DELETE your current Tavern of Spear version
5. Install the newest version of Tavern of Spear. (Installation time is depending on your device)
6. Launch the game wait until it finishes loading then FORCE STOP your game
7. COPY the old "files" data folder then REPLACE the new one
8. Enjoy your game!