Maybe a route where the dungeon acts as a sort of curse agaisnt the gods to prevent them from trying to directly affect the world, Ouranos and the first gods to descend and spread out to try and blind the dungeon so others can also descend. Them arriving first though caused the 3 Big monsters subsequently the "3 Great Quests" also allowing the gods to not have to seal their divinity when on tenkai to have Evilus (and maybe some other gods like gods of war) go nuts with the power having the chaos and war throwing the world out of wack once OEBD dies and breaks the curse it has over the gods. I've only seen seasons 1 and 2 so I don't know much and this is most likely full of plot holes that wont make any sense, but this way you can explore the world more as the dungeon won't have to be the main focus, possibly allowing you to have more creative liberties when going past whats known right now and making this into a story that can for the most part really be your own. I haven't the faintest idea about Evilus nor much else of anything else about the lore of danmachi, but ive really enjoyed the story far and I'll be sticking it out to the end. Thank you.