: The Continuation Arc would be the Karen Traviss Novels. While these continue
: from Ghosts of Onyx, they are so tonally dissonant from the Nylund books
: that I hate to recommend them at all. Ultimately, they have so little
: continuity with what came after that there is no point in reading them
: after Blue Team gets pulled out of Onyx. Karen Traviss dropped some
: contractually-obligated hints toward Halo 4, but otherwise did her thing.

While I didn't have a great reaction to those books in hindsight, and while I'd still struggle to read them due to how blatantly hypocritical the characters are, in hindsight I understand that was the point. Up until the post-war era, Humanity had a bit of a moral blank check. However, the Spartan program wasn't created under those conditions and that speaks to the kind of organization the UNSC really is. K5 is the story of the ugly other half and how Humanity has its own problems that arguably make them as irredeemable as some Humans perceive the Sangheili and other Covenant races to be. (not that anyone is necessarily irredeemable, just that they all have some serious flaws as species and to look down on any other is the pot calling the kettle black)

343i went hard on a distasteful Humanity in the post-war, and while I think that actually makes a lot of sense, that's really hard to pivot to after a decade of triumph with a healthy heaping of blinders in the media you've presented.