I agree with you on this one. It is hard to explain what depression is like to someone who has not personally experienced it. Moreover, mental health issues are not taken seriously in Korea. I also think J0nghyun himself had lost the will to live by 2017. The VCR
@btach posted earlier shows him being defeated in a boxing match. The opponent he was fighting was his depression. He showed that he no longer had the strength to fight his depression. His song lonely talks about how he no longer finds joy in things he once loved to do. Being an idol, it was part of his job to show himself happy and smiling all the time in front of the fans but in reality, he was suffering. Let's not forget that all the conversations about Korean celebrities and mental health started AFTER his death which means before his death it was probably much more difficult to get access to proper help in SK.
K3y and M1nho also wear some of Jj0ng's accessories. I think he was close to the members like you are close to your long-time co-workers. He called only T@emin to 4 things show and he gave his suicide note to 9Nine not his members which implies that he was closer to her than his members. Fans are dumb they believe everything their idols show them in front of cameras. Jj0ngkey, M1nkey, Jj0ngTae, 2min these are all fake ships to make fans believe that they are all innocent virgins who have no interest in women or dating. T@ekook and Jikook used to be so popular but now look at them. The Maknae line in BTS barely interacts these days. M1nho seems closer to Changm1n than any of his members, K3y is closer to T@eyeon and T@emin is closest to Kwonho.
About essem idols appearing less close yes it could be because of intense competition but I also think it could be because most essem idols come from relatively well-off backgrounds. There is at least 1 rich idol in each essem group and not many of them have pre-debut stories about living in poverty. Poorer groups tend to have stronger bonds imo because often the group members have only each other to rely on for support. BTS were closer before they blew up after they became millionaires the bond weakened.