This romcom manga likes to drag itself out but at the very least we're getting some signposting that something has changed between them. It's because a major theme in the manga is about missed opportunities and living within the journey than running to the conclusion.
We got that with the main MC pair, we got that with the teacher pair, we're seeing that in Kouhei's big sister and they're all living in the question and walking towards the answer.
If you've never had a childhood friend, may you meet someone that makes you feel young again.