A "manual" test case I've seen before actually involved trying various things in the software while literally walking into an elevator and having all network connectivity suddenly cut out (no WiFi and no cell radio), in order to simulate what so many people do (or at least did anyway, pre-COVID) regularly throughout the day. I suppose this is also a bit different than just toggling connectivity on the device, since for some time the app and OS both still think the connection is in tact when it's already physically gone, so it may even be useful to help expose other issues this way.

One of the things that's easy to take for granted these days when working on desktop or server software is a mostly stable network connection, but on mobile this goes completely out the window, or down the elevator shaft as the case may be. :)