This is a widespread bug affecting all kinds of devices. It was introduced in iOS 16, and people who game are raging over this. I even experience it in the Hit the Island game, however it’s only dropping frames when touch input is provided as long as I stop touching the display, the framedrops disappear. Is it the same in your case?
Yes and No
In Rally it is during touch. In FF9 is is while the cinematic scenes are playing. In Heckfire it is while your dragons are zipping across the screen AND when you are scrolling around the map (map takes fingers)