A pragmatic pov could say, however: So what? Is it really Kyouya's fault when people make different life choices just because he's around? What if these guys' lives actually became BETTER? Would Kyouya then be a bad guy? I doubt it. He caused change, that's the only fact. We know Shinoaki is a happy mother and married to him, hardly a terrible life. Tsurayuki might have become a much more respected author now that he left game dev writing. Similar, Nanako might have become a famours singer that'S not just known for shitty light novel soundtracks. And Kawasegawa might have become a much more successful person, hardened by how the past turned out.

The point is: People make choices. Kyouya didn't actively manipulate them. He just happened to be there and tried to do the best within the school regimen. Neither did he try to sabotage anyone nor use his knowledge to catch himself a cute gf. It just happened.

But whatever: Any attempts at fixing things now would result in erasing his daughter. That'd be worse than ruining someone's career.