Dazai has been different from the others since his appearance in manga and anime. He was never like everyone else. If you dig deeper and analyze his personality, you can probably draw the correct conclusion that this is a problem for him. A certain complex. I would say inferiority syndrome.
You also need to take into account the fact that he is the most mentally broken character. He was only 15 years old when Mori killed a former boss in front of him. Also, if you read "Confessions of an inferior person" written by his prototype Osamu Dazai, it becomes clear that he has always been like this. Dazai's manga/anime personality is almost entirely taken from the prototype. Yes, and this is a character in itself hiding behind a lot of masks.
In one of the episodes (which one I don't remember exactly), we see his real face. Complete withdrawal from the world. It can be concluded that Dazai doesn't feel anything. No sympathy or self-pity, no love, no reason to live. He lost himself. This was due to the death of Sakunosuke Oda and his last words. Dazai probably feels out of place and out of place everywhere. This may also be the reason for his desire to commit suicide.
Maybe he just wants to feel the power over his body and emotions. In the Dark Era, in a conversation between Odasaku and Dazai, he said that he joined the mafia in order to enter the world of pure emotions and instincts. Even then, he hoped to find the meaning of life in it. Dazai lost himself back then. I apologize if I didn't answer your question the way I should have.