I was able to add the Duo as a simulator, same as the others. Device Hub > "+" > iPhone... > iPhone Duo It did act a little bit wonky when I ran it from Xcode 26.6 initially (opened two simulator windows, no options to switch between open/closed), but once I ran it from 27.1 it's now behaving with all of the different versions of Xcode.

What an incredible bug! On Xcode 14.3.1 and, yes, encountering this error where I build, get to see my compile errors for a second or two, then have them helpfully disappear. Clearing Derived Data did not fix the issue for me.