everything you said is right! Though this is what happened after the ending— a continuation of solo leveling. In this story, Sung Jinwoo is currently fighting a much stronger enemy in the space and that enemy's power somehow shook the world thus creating the new dungeons that appeared 3 years ago in this story. So they didn't remember the dungeon outbreak 21 years ago, the dungeon that's appearing now is a new dungeon outbreak caused by Sung Jinwoo's current enemy in the space.
hope you get it
Also added: why the outer space try to invade earth bcs the "creator" of this universe died with all the monarch. And as I read the novel I think Itarim think that the previous creator was a failure. Luckily sjw as shadow monarch realise this and go to the war before the war go to him. Bcs if that happen the world would be destroy again. The world seems had some kind of survive mechanism. It sense danger again, after so many years so it create another awakening, so the human at least can fight.
I see thanks
omg now i get it cuz i was literally so confuse
So far it's interesting and it's not copy of his father story. Even though I'm kinda confused didn't solo leveling story end after he saved the world and turned back time and everything was "normal" and no one remember that world. Maybe I just understood it wrong, correct me please if I'm wrong