I disagree, there are signs that the MC from the 3rd story is peeking into the more "aro" aspects based on how his previous partners were saying.
But the thing is also, the 3rd story hasn't concluded yet. It's possible that it's just very slow paced. So personally, i wouldn't call it lacking. It's just more in your face on the realism aspect. But that's completely fine. Since as the other person said, this manga isn't about romance or love.

Highkirkenly this was a gem until it got into the 2nd story, (which was still peak in its own way, I think) but unfortunately the third story just...isnt romantic. If it was someone who was also a minor then I would be like hell yeah but theyre really shoving the im an adult youre a kid but I still want you but youre not gay :// in our faces
And even if it isnt exactly like that, its still really just unfortunate its even apart of the story. What a shame