We are sorry to hear that you're experiencing frame drop during the game. Below are the advises for your quick reference:
When the battery is low, the frame rate will drop, resulting in lag and frame drop. Please recharging your phone and try again.

Please avoid playing the game when your phone is overheating. The device's Temperature Control will be triggered when the phone is overheating, which will decrease the frame rate and create the game graphic lag. Also, it's not recommended to play the game while the phone is being charged.

Please avoid running too many apps at the same time while playing the game. When there are too many processes running on the backstage, the graphic might get stuck/lag. You may try to close all processes and restart the phone.

Please setup proper graphic settings according to your device. If you set a higher graphic settings beyond the hardware capability of your device, it will cause your game to lag.

Pay attention to the signal in bottom left while you are in a match or during server selection. The yellow or red signal means your ping is high. In this case, you may try to switch your internet connection to Wi-Fi or 4G, or change the graphic settings back to default settings.