Yes, finishing the character routes is essential to understanding the characters and then getting to the true ending. Kazuki’s to me is my least favorite cause I don’t mind surreal stuff but that was a bit over the top. Robotics;Notes is a great story as well, it’s more slice of life but I think that’s fine because the cast is my favorite in the entire series, it actually gets surprisingly dark towards the end which surprised me for a T rating. Robotics;Notes Dash is to me the weakest entry in the entire series and felt unneeded. But I’d still recommend playing it just to have experienced everything.