Calibre's interface isn't to my liking but since they added the possibility to manage collections/bookshelves ~two years ago for my almost ten year old kobo I love it a lot ^^. Managing collections/bookshelves on the Kobo is a major PITA.
Seems like a needlessly complicated way to do it when the books have series metadata, so props to Calibre for the extra work to support that!
A great discovery for me was that Calibre can convert to KEPUB (subset of EPUB tailored for Kobo readers).