I feel like one episode would've felt like it is enough if they focused on the important subject matter from the get-go instead of meandering around with the plot.
Ruka's backstory would've shed light to an entire football field but they decide to leave all of that rather ambiguious and unexplained.
Definitively a low point of the series even then I believe ep 17-20 although have amazing moments I was the most worried you will enjoy the least. Ofc I could always be wrong.
I would've enjoyed more just Okabe and Ruka having an extended conversation sitting on the bench at night - It would have felt more romantic and personal but that's just my opinion.