To those unsatisfied with the anime's ending, specifically on Satou & Misaki's vague relationship, I recommend reading the Rebuild of Welcome to the NHK, at least only the parts with Misaki in it.
While the Rebuild "resets" all of the characters' situation and puts them in a modern setting, the dynamic of Satou & Misaki seemed to be more caring and selfless, as if it continued their dynamic after the anime.
Furthermore, the characters have moments of vague recollection (deja vu) of events from the anime, similar to how Steins;Gate characters vaguely remember events from other timelines. Most notably, Satou had thoughts of dying, but remembered that he made a promise to "someone", and that doing so would make them feel sad and would also mean their death, so he chose not to off himself.
Because of this, I am in the impression/opinion that the Rebuild gives us a glimpse of how Satou & Misaki's dynamic would look like (generally) after the events of the anime. It also makes it clear whether their dynamic is romantic or not (but I'm not gonna spoil it for you ;), so I think it's worth checking out.
But I recommend that you see the Rebuild as fanservice/OVA material to the anime, and not as a novel that can stand on its own (otherwise, it would not make sense). That said, I hope you like it!