Doom: The Dark Ages DLC is "freaking huge," says director: "It's basically like a sequel"

In other words, "it's massive"

GamesRadar+
How expansion packs used to be. The last game I saw get a DLC that basically added twice as much game to the game was Shadow of the Erdtree and before that, was probably sometime back in the early 2000s before Oblivion released the Horse Armor.
If it makes you feel better the Horse Armour killed the series as they only ever released one game after it.