Notes from Carnet lost or duplicated

I lost a lot of notes created in Carnet. For some of them only the title is shown (even if the preview with Title, expose a few lines but empty when opened). Many other are duplicated. I am stopping to use Carnet. Can I recover the notes ? How to transfer to another notes app on NC ?

EDIT: I found some of the missing files. It looks like there is so many duplicates all empty. It is impossible to delete the empty duplicates.