Awesome! I had the exact same issue. When testing on the Development environment, I had never added this many images or very large images. So CoreData would never extract image data to external ckAsset files / objects and the field was missing from the schema on the iCloud Dashboard. The trick is to really force CoreData to extract the data to separate assets by adding a lot of large assets (in my case images). Thank you very much!

This is the correct way to do it. In fact, the Watch app will sync to a different Key-Value store. The iCloudKey-Value Store needs to be changed manually in the entitlements file as you said. However, I decided to change the Watch app's entitlements file to use the bundle identifier of the iOS app by setting it to $(TeamIdentifierPrefix)com.my-company.myApp

Yes that's it! (And it is still that way in 2022, so 2 years later)

Yes, that's what was missing. Thank you! It's weird that XCode does not automatically add the watch app as a dependency, though.

I can't follow you. When I first setup the Watch target in XCode 13, XCode created two targets: one Watch App target and one Extension. This is also how it is shown in the latest tutorial: https://developer.apple.com/tutorials/swiftui/creating-a-watchos-app But when I moved to XCode 14 and set up the new single-target for the Watch App is not included in archives and submissions anymore. When I inspect the archive, it is not included and in TestFlight app details it states "Watch App: No".