Nagito basically effectively gaslit himself all his life into thinking hope is the only constant to cope with the trauma from his luck cycle, and that unconditional love is an unreliable myth because hope is paid for by talent (the ingredient for fighting against circumstances and affecting change); all that ultimately robbed him of his blossoming connection with Hajime — it actually pushed him to destroy it with his own hands.
The fact was that Hajime made him comfortable and welcomed enough to express the notions born of his innate empathy and candid feelings without compulsively producing hallowed reminders of his own unworthiness every two seconds (because Hajime WAS talentless and everything precious and golden about him was isolated from talent), and yet, when Nagito realized this all came from the absence of talent and the presence of something else — non-absolute — he just detonated it all willingly. He even had to cover up his ‘inferior’, ‘sublunary’ love for Hajime with a sentiment justifiable with the supremacy and eclipsing worth of hope (“please know that I love y—I love the hope sleeping inside of you...”).
His story in DR2 was always meant to be a tragedy. It makes you wish he could live separately from hope, to just let himself love Hajime with his rightfully soft, sensitive and vulnerable love and be loved for what he conditioned himself to think was worthless in turn.
