Playing on a rooted phone

Hi, i'm new in fgo and i'm playing the game on a zte blade a521. My problem is that the phone only have 8gb of internal storage and somehow it doesn't have the option to move apps to the sd card nor the one to use it as internal storage so my only solution is to root the phone. Is there a problem with that? Like a ban or something? Do i have to install the game in a diferent way because the phone is rooted?

Also i'm playing the game with only 1gb RAM. It runs fine except during loading screens where it gets slow. I'm currently playing the end of the first part, not even a single crash yet.