Here's one way to get the app data if you have a mac:
* Install and run "Apple Configurator 2" (this is Apple's software for businesses to manage many ipads)
* Connect your ipad, select it in the app, click the "Add" button in the toolbar
* Find Civ 6 in your list of purchased apps, and select it, wait for the download to finish
* Configurator will notice that the app is already installed and ask you what you want to do. Don't click anything yet.
At this point the .ipa file has been downloaded to your Mac, and configurator won't clean it up until it thinks it is done. For me, the file was at:
~/Library/Group Containers/K36BKF7T3D.group.com.apple.configurator/Library/Caches/Assets/TemporaryItems/MobileApps/307C94EB-D0A6-4A62-BF30-86754C40BB64/1235863443/Civ VI 1.0.4.ipa
If you're using the finder you'll need to hold down Option and select Library from the Go menu, then navigate down until you find the ipa file. Some of those numbers may be different, but basically anything under MobileApps that has the right name is probably the file you want.
* Copy the file somewhere else (Desktop or wherever).
* Tell Configurator to Skip this app. It won't do anything to your iPad and you can quit the app. It will also clean up that .ipa file under MobileApps, which is why you need to make a copy before letting Configurator continue.
* Rename the .ipa file to end with .zip instead of .ipa. (.ipa files are how apple packages ios apps, but internally they are zip files). Confirm that you really want to use .zip as the extension.
* Double-click the Civ VI zip file and it should expand into a folder containing the contents of the game.
* Open the Civ VI folder, open "Payload", then right click on Civ6_iOS64_Metal_FinalRelease and select "Show Package Contents". You should see all of the game data files here. For example Base/Assets/Gameplay/Data has a lot of the xml files that determine gameplay.