iOS Safari at least used to limit the memory, particularly the WebGL GPU memory, to something like 15 MB after which it would hard crash. I think this might be what's happening here since all of the websites are iframed (there seems to be at least ten).

Fwiw, it's very slow on desktop Firefox with M1 until all of them finish loading.

I did some more performance optimizations including lazy loading. Let me know if it is still slow.