Responses
This is actually true and confirmed. Knowing the end of the novel was them HEAVY implied, so yeah, the focus is not on their romantic status but more like, family to each other
Shj even referred to hyj as "yeobo" in side stories of the novel. And it is a term only used by marriage couple. So, they are canon but the focus of the story is not romance.
factsss
I think this is not labelled as bl because the story's main focus is action, not romance. Otherwise, how they act like is certainly not straight