I will honestly not be satisfed with another end than Uta/Kaoru. I know at this point the odd are not in their favors but i don't really care.I never really those kind of bad ending.
I mainly want to read well-told stories. Failing that, if I’m interested in the characters as individuals at all, I want to see stories that “do right” by the characters—not necessarily a happy ending, but whatever feels like a suitable one, given the arc of the characters.
I don’t see how a Kaoru/Uta endgame ever comes close to either one of those goals. From a storytelling perspective, just getting the two of them back into physical/emotional proximity would entail a U-turn in the way the plot is going, and, as I’ve been saying, to my mind Uta is way too good to be saddled with a passive-aggressive emotional trainwreck like Kaoru.
At the beginning, Uta being more mature and self-aware than Kaoru was a kind of cute way of signaling that these two might be better off together. As things have developed, the most obvious way of getting Kaoru and Uta as a couple is a major authorial ass-pull, which to me would be a disaster for Uta as a person.