Volume 4 is shaping up to be the crescendo of the series. Everything about it right now is perfect. Kimura is using the Shoujo manga trope of improving yourself for your love interest for the sake of yuri now. She understands her own feelings now and is starting to comprehend Hiyama's erratic thought patterns as well. I believe she already instinctively could tell Hiyama's true thoughts and wishes before, but now she is actively working with those assumptions... and succeeds.
Mizushima (finally elevated from boytoy status) has awakened to the yuridanshi side it appears. He has been more or less a plot device for most of the manga and a total doofus, but I'm now honestly glad for such a refreshing take on an eyesore role. He knows exactly where he stands and he just seems to enjoy when the people around him are happy. Playing wingman is clearly not his strong suit, but at least his straightforward honesty resolved a lot of issues.
There was a rough patch with all the misunderstanding drama and the world-shattering logical nonsense of Kimura thinking Hiyama would consider her weird for liking her (what happened to the last 30ish chapters of her confessing every day, Kimura you dolt?), but the moment she finally stopped deceiving herself things have only become positive. And even that very tedious drama was actually a really clever subversion of Shoujo manga tropes. Every line and set-up was so misleading on purpose. I think I have never appreciated how being dedicated to sticking to a Shoujo manga script while still totally being 100% yuri is quite amazing.