I think the teacher x Nanjou x Riri stuff is so far a weak part of this series. We don't get to see any upsides to these relationships, only downsides. We learned nothing of consequence about Riri in this chapter either.
Unlike the case of Sayaka's iconic unrequited love for Touko in Bloom into You, Riri x Nanjou don't have a confidante relationship, a friendly rivalry, or any other interesting dynamic. Uda x Riri also have more going for them by the virtue of (1) Uda being already well developed through her interactions with the main duo and (2) them having gone out together to have fun. But I would see it as an improvement even if the series simply committed to Nanjou x Riri, and gave them stuff to do together, instead of this aimless walking in circles.