I honestly think Nino is endgame and the remaining arcs are to resolves any remaining issues between Fuutarou and the rest of the quints. The two of them just click in a way the others don't. Yotsuba was a coward, Miku was indecisive, Ichika was treacherous, and Itsuki was too slow to realise and act upon her feelings. Notice how Fuutarou doesn't embody any of these traits. He's blunt, straightforward, confident, courageous and has a no-bs attitude. Guess who else is like that? Nino and her Fuu-kun are a great match and she's totally rocking the mom look in the future-past chapter cover.