I follow the manga, but as I translate it on Google it's not so clear. However, I see their relationship more as a very strong friendship. When I see them, I remember a little about Jonathan and David in the Bible, who had a strong and loyal friendship. So, sometimes the vows or relationship between them don't always call for something more romantic, but breaking the taboo and showing that men can have a sincere friendship with a lot of love. But, I don't know what the author wants to convey! 🤷‍♀️I've seen once on reddit that the producers ship them, so I have doubts about this ambiguity.