I was on Zoom with my mother playing cards recently. She often has trouble with accidentally closing the card game. I don't see how this problem could possibly be improved if it actually were impossible to have the card game open at the same time as Zoom. She would need half a dozen iPads.
(Of course, her solution often is to use a dedicated device for the card game and a dedicated device for Zoom, but this is an expensive solution for something the OS could be designed to handle well, and even if you can afford it it's a mediocre to bad solution.)
A simple mode can have togglable features as well (and all made simple).
You turn on simple mode, then you turn on split screen. All controls optimized to be simple, discoverable, and no hidden controls (as opposed to a normal mode, where all controls should be fast, intuitive, and keep you in a flow).
(Of course, her solution often is to use a dedicated device for the card game and a dedicated device for Zoom, but this is an expensive solution for something the OS could be designed to handle well, and even if you can afford it it's a mediocre to bad solution.)