If you want to go a step further, calibre-web[1] can act as a backend replacement for kobos servers (and proxy to kobo) so whenever I sync my kobo, it gets any new books from my calibre library over wifi.
Another tip: if folks want to use DRM'd books they've purchased indefinitely/however they want: NoDRM (a fork of the no-longer-maintained DeDRM) makes bringing in DRM'd books into Calibre completely painless.
Do the dev teams overlap?
I want some self-hosted "store" backend for my kobo but am still traumatized by the UI after trying the desktop version.
[1] https://www.reddit.com/r/linux/comments/98mob0/light_epub_re...