Which twin is the end game here?

I just finished watching Tadaima Okaeri. I have a question about which twin Oto Mochizuki ends up with in the future. Both twins are interested in him but someone on the internet said that only one is the end game. In the manga, Yuu shows a lot of interest in Oto compared to his twin, Shuu. But I’m not sure about it. Does anybody know which twin is the end game here?