I was seeing that Yuzu and the Red Blood cell 3803 have some similarity, for example the red blood cell did the best to overcome her weakness (getting lost), she had to make people show her and she made many mistakes, but she never gave up and finally achieves it. In the same way, Yuzu has done her best to maintain her relationship with Mei, both as sisters and lovers. She did not do so well, she has given the best of her, she has friends who have supported her and she has not given up either.
But unlike the Red Blood cell 3803, who succeeded, i do not think Yuzu has the same luck, because in some way it is not the function of her or her destiny.
It would feel too forced and meaningless that in the end magically Yuzu and Mei end up together.