Thanks! While this does allow me access to the second instance of Edge, it still seems unnecessarily inconvenient.
This used to be extremely straightforward - when activating Edge from the home screen, if Edge was already open on the other screen it would launch the "other" instance. I could dismiss Edge on either screen, temporarily use another app, and switch back to Edge by tapping its icon on the home screen, all without any disruption to the first instance.
Now I have to find any random link in the primary instance, long-press, and open in new window, then close the unwanted tab, which seems excessive.
That said, this is at least a functional workaround for now. Once I actually have two instances, the app switcher interface works well enough.