This did help, thank you. Although I didn't end up using the history, fetching data from the underlying container updates the data model with changes that were written in the App Intent. I ended up using the shared UserDefaults to store the persistentModelID that was updated, and then read that in the main app to fetch the changes and update the UI.

I actually got this working now on iOS 17. I made my App Intent inherit from LiveActivityIntent and ensured the file is added to the extension target and main app target, and now the changes are syncing up correctly in iOS 17 as well.