Unless Nanashi wants to go through them finding a bit more footing on their elected paths during young adulthood in college, yeah this is basically the climax of both of their character arcs and at least for the stage of relationship most manga like this does.
they could do how they develop intimacy and how they growth as adults in tandem for that college phase (basically fast forwarding the last year of school for Nagatoro, and lightly covering the first year of uni for senpai, and pick up a slower pace for when they're both out of school), but who knows if Nanashi feels that's worth to go in depth.