I have the same issue, Xcode 26.4, Objective-C project.

The guide is helpful, thank you. Hint: use this value for the key 'Delegate Class Name': $(PRODUCT_MODULE_NAME).AppDelegate assuming that the name of the delegate class is actually AppDelegate. I started with the value 'AppDelegate' for this key, and got the following error at runtime: UIWindowSceneSessionRoleApplication contained UISceneDelegateClassName key, but could not load class with name AppDelegate