could easily be caused by not having enough RAM and having to shuffle art assets between storage and memory

In iOS there is no swap:

In iOS, there is no backing store and so pages are are never paged out to disk, but read-only pages are still be paged in from disk as needed.

(https://developer.apple.com/library/archive/documentation/Performance/Conceptual/ManagingMemory/Articles/AboutMemory.html )

Which counterintuitively actually makes it more RAM capacity demanding than macOS. macOS’s 2-stage swapping with compression (and absurdly fast NVME) is in fact quite good, iOS has to fit in RAM and RAM only.