Responses
basically yeah. they're connecting him with dissociative identity disorder (formerly multiple personality disorder) which is when a person creates alternate personalities to cope with severe trauma. so basically his current presenting self created the non-omegaverse life to create distance from/compartmentalize his trauma. but the trauma is compounded from previous regression attempts and not stuff that's happened on this go around.
Imagine your already broken and crazy, obviously you'd want to escape from that "world" but that is your reality so instead huimin as an artist, who has that ability to "think creatively" which is to create a dream world aka novel as a means of escape, and huimin being depressed as fvk would definitely be using his delulu as solulu therefore he can't differentiate reality from his imagination which created his disorder?