PSI: this is not meant to come off as rude in any format!! My apologies if it seems like that!!
1: the official pride panel for webtoon only has canon lgbqt+ characters. they would have no reason to add jay if he wasn't one. You also need the author permission to do so.
2: the official account of the author has alot to prove, he makes mini things about the characters talking about things they like and other details. He stated that jay likes Daniel & so have several other characters within the story.
3: their are several more things that hint at the fact jay has a crush on Daniel, several characters have also hinted at it. Its not a headcanon that he likes Daniel, nor that he's apart of the community both are more then implied at this point!
The author is feeding us right now, I just know Jay was kicking his feet around the moment he was given some privacy.
Also in this arc I really hope we get to see more of Jay backstory, like most of us already know he was disowned by his father for being the biggest boy kisser known to man kind, but I wanna know what lead you to that, like I need to know more. How his father found out, if his siblings know, if he maybe liked somebody that’s just like Daniel.