I am also having the same issue. Here is how I am trying to import multiple URLs from Files: I go to the Files app, select the folder in iCloud Drive, click the "3 dots in a circle" icon in the top right corner, choose "Select" from the menu, select several files, click the share icon in the lower left corner and then choose my app icon. My app gets launched, but "scene:openURLContexts:" is called only once with an array of contexts containing only the first file.
I have a couple hundred files in a folder on my iCloud Drive, and I want to import all or many of them into my app (as I understand my app is not able to access the iCloud folder contents directly). It is going to be incredibly tedious if users need to import files one at a time. Is there any way I can import multiple files in a single operation in iOS 13 to 15.4, or do I really need to wait until Apple releases an update to "allow multiple files in the future"?