Subverting expectations... this is really overused phrase nowadays, but i sincerely think it fit the finale of this arc, to put it plainly... this finale is crap, but it isn't. For all intents and purposes, it accomplished a core necessity of this manga as a whole, Denji personal growth he understood so many little facts of life that we normally take for granted and really reached a really mature conclusion, you might say that his conclusion just put him in the same place he was before but now he has a more nuanced understanding of what will necessary for him to live the life he so much desires.
I am truly impressed, this author toke some of the worst errors a writer can do and turned them in the strength of this arc... this is... amazing.