It's Iooking more and more Iike a dud with each passing chapter. In the end, their "feeIings" will just be relieve over their family and support structure not being broken by their circunstances or whatever and Kotono will just be dismissed as "too young"/"surely it was all a misunderstanding".
Like 5 toubun where one of the quintuplets' arc was literally just her dealing with stuff about her mother and still ending up blushing over the possibility that the mc liked her, but even then, only for 1 chapter.
At least Miku worked to change herself. Kotono (and the rest of them) will be the exact same flat archetype they started as by the end.