I read something about this on Reddit where Shirohama was more so warming up to the idea of his friend being in a homosexual relationship. In addition, based on the school festival arc of the most recent chapters, it seems the author is setting something up for him and Ugawa (Sasaki's college friend).
1. We have Ugawa who wears masks to hide his identity at the anime/manga convention and the school festival, possibly because he might be a popular Otaku like a cosplayer or something else.
2. Kyouji feels like he saw Ugawa somewhere other than with Sasaki near the candy shop, perhaps at a convention or on social media.
Overall, I think they might become the next pairing in the story or at least become Otaku friends.
I wonder, does shirohama kyouji like miyano? IHAVEN'T READ THIS IN A LONG TIME and i just chose a random chapter and he said that he somehow feels “irritated” when he thought of miyano and sasaki being alone together