100% bg!! when yj starts working for him he just immediately finds himself attached, it starts as a kind of puppylike idol adoration thing because yj is this cool older (by barely any years, but still older) guy that seems to have the answers for any questions he has and he finds himself feeling so safe and heard with him that over the years it just blossoms into something more for him... other than wonyoung and to a much much smaller extent his mother (shes not as much of a reliable source of reassurance as she used to be for him), yeonjun is the one person who he feels doesn't see his more gentler, emotional personality as a negative. he loves his family but theres a lot of pressure put on him by his father to be the perfect successor as hes the first born son and he doesn't live up to these expectations at all, especially when compared to kyuwon who is basically perfect in every way, so having yeonjun next to him reassuring him that these things are strengths rather than weaknesses and that its okay for him to just /feel/ is a really grounding thing for him

he doesn't have any internal conflict about the way he feels either, at least not until wonyoung is cursed and he has all this guilt about his attention being split between his misery with her situation and getting excited when he feels like yeonjun is finally returning these feelings that he's had for years