Apparently, the app has been removed from the App Store.
If an app has been removed from the App Store, you can no longer download and/or update it.
I also have some paid & free apps here, and those apps have been removed from the App Store.
Sometimes an app is removed from the App Store because the developer has stopped updating, or for other reasons.
Last year I also had multiple apps with the same message, such as:
Click Keep, then nothing happens, so I clicked Delete.