Guys the easiest way to use the non modded version while, keeping your account is to BIND it over with your email. I do this whenever there's update takes longer. Don't use codes the game already implemented the log in via email it's much easier to used. here's what i do.
(there's an update)
1>I go to the storage, data and find the fgo data if u find it rename it and add like a 1 on the last sentence like example from "aniplexfgodata" to "aniplexfgodata1" so when uninstall the modded it will not delete the data.
2> uninstall the modded fgo and install the non modded (you can find one on apkpure) once u find and download, install it and run it like usual once it says u need to download the data click it and exit the game.
3> Go to the storage, data and find it again now what u have to do here is to delete the "aniplexfgodata" created right now by the game when u installed it the one with the non "1" after this rename the previous data u modified and remove the "1" go back to the game.
4> now when u log in just like how u usually log in true codes but this time you'll log in via email. the perks of this is you will never forgot to bind codes or forgot it because u already bind it tru your email. u don't have to log in via codes.
i hope this is easy to understand lmfao okay im done yapping~