I’m using a pretty complex UI for my game. It has a start game ui that disable itself when the game starts and enable another ui that has lots of sub item(for a lost screen ui) disabled. During gameplay, most of the UI elements are disabled, but the game shows huge lags during gameplay that freeze the game for up to 1 second. All of this ocurres on iOS products(iPads and iPhones) but if I build for android the game works marvelous, without any spike and a very good performance.
Is there something with the UI that could generate problems in iOS but not Android?
What compression settings are you using for the assets? Are they POT (power of two)? iOS only supports PVRTC compression, so your UI may be displaying truecolor assets instead of compressed ones (that is the fallback if your texture isn’t POT).
Try using sprite packing. Also use the framedebugger to find out what is actually being drawn. Hook up the profiler on a build running on iOS, compare that to a build on android. Also this script with frame debugger is great to debug that sort of thing: GitHub - handcircus/Unity-Resource-Checker: Editor utility for unity to help check resources in the current scene (including active textures, their sizes, materials, meshes and which objects are using them)
Keep us posted on your findings