Cross platform as in most CPU intensive code is in C++ that is exactly shared between both, only trivial but obviously needed differences in input handling. And for Android the renderer is Vulkan and for iOS it’s metal, both essentially identical in how features are used.
Some super high end Android phones come close in some cases, but on average iOS devices wipe the floor with Android ones.
I want to emphasize that on top of Android HW being slower on average it is also hampered by the decision to use Java. Some api’s are Java only requiring JNI, which is slow, to access. Another issue is GC pauses, they are small but can result in skipped frame here and there, making the experience subtly worse.
And Apple also benefits from being able to set their own page size and probably from getting to have caches that are virtually indexed and physically tagged rather then physically indexed and physically tagged. Doing address translation in parallel with way lookup is a nice little performance boost. There are rumors of other cleverness in the cache heirarchy from control of the OS but I don't know the details.
https://www.anandtech.com/show/14892/the-apple-iphone-11-pro...
Besides that, there have been plenty of articles where they found that Android manufacturers were detecting when benchmarks were being run and cheating.
check your conclusions - 90% of articles with rocking iphone performance cite geekbench.