Unstable FPS when the player is moving (walk/sprint)

Unstable gameplay or FPS when walk or when you sprinting. Even tho my device is Snapdragon 865 ram 8 internal storage 256 can't handle this, and even on the lowest render chunk and graphic still won't get better gameplay. Is there any help for this? Or maybe the dev can make this problem fixed by doing anything, idk. I can't enjoy playing with this unstable fps