We recently encountered this crash on iOS 14, but not iOS 15. Thanks to djehrlich's pointer, we were able to narrow it down to the same situation: GeometryReader inside List inside Tab.
The crash only happened on archive builds, not when attempting to build from Xcode (debug or release). We were able to reproduce the crash by using ad hoc builds from our CD server and narrowed it down to when we introduced the GeometryReader inside List.
Curiously, it seems that Xcode 13.3 may have fixed the crash. The builds made with Xcode 13.2.1 crashed, whereas the builds made with Xcode 13.3 no longer crash.