Cool game, but I have a problem with graphics: I can't change from 30 fps to 60 fps, but my phone really have 60 fps

I like the Game... But the Graphic settings doesn't have an option to increase frame rate Please Update it fast. My Phn got 90 fps in PUBG but for this one gets lagWhy?

I have lowest mediatek processor This game was giving me 60 fps with max graphics