I hope the next update fixes this. I guess making sure you got enough space and finding settings to allow third party apps is all I can recommend now :/
I downloaded it and played it on my phone. I think it might be a ram issue on the phone because my old phone is struggling too. a lot of the backgrounds and characters have renpy applying filters on them to make them look day and night, it has renpy adding the outlines to everything clickable too. along with the characters moving about and stuff. Right now It'd take forever to apply all of that manually on the pictures and we would also need 3 versions of all the pictures in the game and then having to compress everything by a lot.
There might be a small chance I'd do that in the future once the game reaches closer to 2gb in size. Sorry I can't help you much