I'm not familiar with epubor, and I run on Windows, so I've no idea about Linux compatibility, but you can check on the actual github of the plugins (linked from here:
https://www.mobileread.com/forums/sh...d.php?t=253119)
That said, since the content of .kobo/kepub is what it's linked to your Kobo account, you can get the epub/acsm files of what you purchased by logging into your account on their website and then going to My Account -> My Books -> click on the three dots under "Actions" -> Download