Due to the big amount of complaints, Ill be writing here the Mod setup method that was explained just above in case someone missed it:
>Download the game on PlayStore.
>Login into the game.
>Download all the data (should be 2 or more big downloads). (When you can freely navigate through the UI, when YUI-chan ask you to explore yourself & when the login reward appears, it means you have completed the tutorial).
>Go to Menu -> Setting -> Account to bind your account. Sign up first if you don't have existing BANDAI account. It should say account binding is completed if you have done correctly.
>Go to Android/data, and rename the folder found there from com.bandainamcoent.saovs to something else (like com.bandainamcoent.saovsX).
>Repeat previous step but in Android/obb instead.
>Uninstall the game.
>Download and Install Modded Apk provided here. DO NOT OPEN IT YET.
>Rename the previous 2 folders back to com.bandainamcoent.saovs
>Enable Overlay Permission.
>Open the game.
>Transfer Account in the Login Screen (Top left icon).
>Enter the game after successful transfer. Data download should begin.
>After that you will enter to main menu.
>Restart the game & login.
No error codes should be happening now.