As I mentioned above, Xcode is suggesting to migrate all 76 Swift package dependencies, regardless of whether they target Swift 5 or not. These are Swift packages, so there are no build settings as one finds in a traditional Xcode project. The only option available is to specify the target Swift tool chain version, which is set to Swift 5 for all but 3 dependencies.

Thanks for the info. We look forward to Apple fixing this issue in a future version of Xcode.