^There was never a ship for Karen till Honoka arrived - and she fits her perfectly - and clearly in cannon has a huge crush on her at the very least. As for Kuzehashi, she clearly also in canon is matched with Karasu-chan - by maybe also a crush, but at least admiration.
I don't recall seeing a single hint of crush / romance between Karen & Kuzehashi. I know she is closest to Karen of all the students, but it never was in a way where they had that sort of chemistry.
Yes, my problem is that those "canon" ships are just painfully meh, neither of them can come even close to the chemistry created by the interactions of Kuzehashi and Karen, whose personalities fit each other perfectly. Of course this is my own personal taste, but Honoka's addition to the franchise was so obviously only done to pair up the spare that as an amateur writer myself, I can't help but wince. Again, I know people disagree, I'm just happy at least artists stick by the ship I feel superior.