I did a little experimenting between iOS 13 and macOS Mojave (not Cat) using iCloud, and have what could be a workable solution. It does require a manual step at the end. Catalina may help, but I am not sure.
- iOS 13 lets you pin a folder to always keep it downloaded. This is key if you use Scrivener without network access and forget to grab the files before you leave. I also dragged this folder to my sidebar to help with the last step.
- On iOS navigate to your iCloud Scrivener folder and tap to open a file
- Scriv will prompt you where to save the file: On My iPad, or Dropbox. Choose On My iPad.
- Edit the file to your heart’s content.
- Back all the way out of Scriv and double-check the file save date is accurate.
- Drag the edited file back to the sidebar folder. I did this to help with the navigation. I chose overwrite the existing file, but you also have the option to Keep Both.
- I opened the edited version in macOS Scrivner and got the familiar synced changes view.
The key to this is finally in iOS 13, the On My iPad folder is exposed for general navigation in Files easier than it has been, It’s a manual step at the end, but at least now I can start getting away from only using Dropbox to Sync Scrivener. I feel this method at least replicates the idea behind the iTunes transfer without needing to use iTunes. Catalina might help with the last step, by showing this in Files, but dragging the file back to iCloud does the same thing.
Obviously, the usual disclaimers apply. Make sure your backups are good before you try this with a production file.