Considering it's just one volume, there was a satisfying arc to the relationship. Nina managed to become the person who Mao turns to for comfort, which was not quite the case when they were in high school either. I'm comfortable with thinking of this as a grey area in terms of "yuri", but this feels like a happy/hopeful ending.
hmmm i get the whole debate over this being yuri or just subtext and my opinion is... doesn't matter i guess. they both don't end up with men in the end and are clearly the closest with each other so it could turn into them dating in the future so i'm happy
That description also applies to Tropical Fish Yearns for Snow and that's subtext. I don't think the bar should be "don't end up with men".
Instead of how plausible it is that they will date in the future, we could focus on what we've seen so far. The relationship status of the leads by the end is important, but I also like to consider how that status came about and how the story frames it. In this case, for example, Mao drops the shitty male FWB thanks to Nina's efforts after the latter has been itching to get rid of him the whole time. Maybe more straight girls would find that aspirational in 2026 than I would expect, but...