This manga plays with a lot of mature themes, but those rarely extend beyond the sexual. Saeko is an entirely unlikeable, if somewhat relatable character, and with the introduction of someone who genuinely loves Miwa and whom she seems to love in return, I can't, in good faith, say I'm rooting for their relationship any longer. Miwa has been clueless to a fault in order to facilitate Saeko's character development, and at this point, it's becoming incredibly frustrating. Saeko has, on several occasions, recognized that she needs to talk to Miwa. And on every occasion, rather than speak to her, she just... externalizes those feelings in an overtly obvious way — that then get ignored for no discernable reason.
You could make the argument that Miwa is a habitual people-pleaser, and while I can agree with that to some extent, at this point, it's just getting to be a bit silly. What was the point of that entire arc she had if she's going to... continue just to let Saeko push her around? In twenty-six chapters, the only characters who have gone through a real, tangible arc are two of the side characters. Which, don't get me wrong; many of the problems Saeko goes through are incredibly relatable. In particular, the comphet she experiences in highschool rings waaaaaaaaay close to home with me. Her trauma regarding the bullying she received for her sexuality also hits a few notes that made me think back to when I was in high school. And on a similar note, I empathize with Miwa and her struggles to stick up for herself. They have very relatable and realistically depicted issues — to a point. As of the latest translated chapter, they are four, possibly five months into their relationship and have yet to have a serious conversation about their interpersonal issues. That, combined with their individual recognition of the need to talk, makes the drama feel forced and manufactured.
Which brings me to the most significant issue. Saeko is just... not a good partner for Miwa. At all. They could have chemistry, but the author's unwillingness to have them communicate about literally any of their issues instills the notion that they are diametrically terrible for one another romantically. And sexually. They don't even have real sexual chemistry beyond an ability to turn one another on. Miwa has demonstrated a clear and vocal desire to top, and, on the opposite end, Saeko seems like she wants to bottom. Yes, her trauma makes it impossible for her to enjoy that (currently), but it also robs Miwa of the chance to effectively top her since Saeko is not giving the input that she clearly states Miwa needs to listen to. A one-sided sexual relationship does not mean they have chemistry.
tl;dr This manga could be great, I want it to be great, but it fails to do much of anything with the themes it's presenting. They have so much potential to be great partners for one another, but they fail at every possible turn.
On a side note, I remember seeing someone mentioning that this manga is why you don't see wlw relationships progress past the courting phase. To which I disagree. Wholeheartedly. The biggest reason you don't see many relationships, straight or gay, progress past that phase is because most authors don't know how to write compelling stories past that point.