I like that OSMC provides, via Kodi, the ability to open videos, images, and audio files. And I’ve used OSMC to launch RetroPie for games.
The missing piece of the puzzle for me is viewing PDF files. For whatever reason, the Kodi team doesn’t seem to think this is a natural fit for Kodi. But is there some way that OSMC could launch an appropriate external viewer for PDF (and maybe epub) files?
(A similar question was asked three and a half years ago so a lot of time has passed, and it didn’t cover using an external application)