Forum Discussion
Sorry to hear about the trouble you're having on your iPhone. Have you tried restarting the device, checking for software updates, or reinstalled the app? Those can help clear up in-game issues like what you're describing. That's a really nice device which you should be able to play on higher settings, but if you go to the in-game Settings and select preferences, there is a graphical slider you can adjust to a lower setting that can help boost performance. I recommend trying that to see if you notice any difference. It might help.
If you synced up to your account to Facebook/Apple/Google your progress will be preserved when you re-install. If you play on guest mode that progress is lost upon reinstalling.
iOS Troubleshooting
https://help.ea.com/en-us/help/mobile/troubleshooting-steps-for-ios-apps