Meanwhile Hyunjin & Changbin are very used to having to be closeted. They might even still be trying to work out if they're actually queer. They met & became close as trainees before Stray Kids, possibly even before 3racha? Unclear.
(Hyunjin talks about going to stay with Changbin, meeting his family & friends, back in their early trainee days. I think he also said that he hadn't slept over at any other trainees' homes.)