How best to deal with recovered files in Version 3 upgrading from v1

Is there a way to convert a long text contained recovered files back into the file structure of my document?
The Recovered Files document carries dotted lines indicated original breaks from one doc to another – I would like to restore at least the breaks and thereby perhaps restore the files to a scrivening-style run of texts

If the Recovered document is outside the project, you can use the File → Import → Import and Split command.

There’s no way to automatically split a document inside the project, but the Document → Split command is pretty fast.