Game lagging?

hi!! i just downloaded the game because i wanted to try it out, but for some reason it's horrifically laggy during battle. like, i barely see anything? it's like 1 frame per 30 secs at this point. i've even gotten notifications that my phone UI isn't responding. though when cutscenes appear, everything works well. i'm not sure what caused this. is it because of files being downloaded in the background or is my phone just too weak for this game? ☹