[lumping-sugar66]

Isn't there an Export Highlights function in default Kobo reader?
Anyway, there's also the annotations plugin for calibre will let you import your highlights from your book to calibre. I have ever only used annotations on one book, but I read it on default kobo reader so I know it works.

See the attached picture.

And I think with KOReader, you can sync metadata, across multiple devices using KOReader Sync. The developer enabled that feature 2 weeks ago. You still need Calibre to be your middleman and keep everything in sync.