Massive performance lag on iPhone 11

[Wellsdog86]

I've just changed from an iPhone 8 to an iPhone 11, the difference in gameplay is phenomenal, on the iPhone 8 the game ran like a dream, since getting the iPhone 11 when doing raids, GA, TW, TB and especially Squad Arena the game is really laggy, just tried on my iPad and that was absolutely fine. 

When are CG going to fix this issue? It's driving me nuts. I have submitted a case, seemingly so have countless others.