I don't know how to do it so i can't be specific, there are a few porters on f95 that are starting to do this regularly ("wills747" and "blackeye." Offhand)
It's possible to use an rpa file to archive and dump content into the Android version post install. With it being a single file it's fairly easy to do as well.
Towards which end, you should be able to create an rpa of the entire prologue (not the shell or new chapter) and have it as a once off download for people if they need to start from scratch. That way the part that's updated by the apk file is always the newest content and it should remain simple on your end too, so you only have to make another archive after each chapter.
Just a suggestion, game looks good so far, enjoying it. Good luck