We have exactly the same issue. We can fetch a device token on the iOS 18.6 simulator but not on the latest iOS 26 beta 5 simulator. However, it works on the physical device. I have reported it in the feedback app: FB19400926

It seems that the issue has been resolved with iOS 26.4 and Xcode 26.4. It least my "didRegisterForRemoteNotificationsWithDeviceToken" gets called.