you know what? i think you're taking inspiration from the wrong source. DoL is a good game for what it is, but what you're going for seems more like a cross of Abyss Diver interactive...and Corruption of Champions. specifically, the Xianxia mod. more specifically, the Ebony Labyrinth in the xianxia mod.
allow me to explain if you haven't played it.
the ebony labyrinth is an infinitely looping dungeon that gives exp rewards for every ten floors you explore. every fifty throws a unique, labyrinth-only boss at you that drops unique gear and transformation items. every hundred floors contains a pool that you can use to upgrade a weapon into a legendary/unique variant. every time you explore up to fifty floors you have the option of dropping 'down' a level, that increases the difficulty and exp/money rewards accordingly.
now, this is a game where you explore a hole that gets progressively deeper and more dangerous, and more difficult with rewards to match, i assume. you could do what i think you're going to do with this, which is make each floor a unique thing that has its own unique enemies, curses, and locations...or, you could take from the Ebony Labyrinth. you could make it so every ten floors you fight a boss, and after fighting the boos you get a drop related to that boss; a weapon, armour, a transformation item, or even a unique companion if you do something special beforehand - that is, if you're adding companions. after beating the boos you get the option to retreat back to the safe zone, or to drop down a level. the next level is much harder, composed of fifteen floors, and every level afterwards goes up by five. so floor three is composed of twenty, floor four of twenty five, and so on and so forth.
the point is, all you'd need to do is make the general enemy set up of the level, and what drops and rewards there is a chance of getting, along with level-specific curses and whatnot. you won't have to handcraft everything because all you need to do is make a general outline for now, and fill it in as you go.
an example of what i'm envisioning is this; let's say level one is a plant-based floor. so the enemies are plants and things that thrive on plants, like insects, living vines, trees, things like that. starting on floor one you get the basic bitch enemies, like the weakest insects and the easiest vines. then as you get deeper you find yourself fighting harder and harder, and much more common, enemies. the boos at the end is suited to the theme, so something like a dryad that controls a grove, or some obscure nature spirit of a sort. you kill it, it drops you a themed weapon, armour piece, or transformation item, and gives you the option to go down to the newest level or not. this incentivises the players to go up, prepare, and go through it all again to get their level up and fight the boss again to drop more of the armour set, or more of the tf items. the curses in the area would revolve around that theme, too, so anything to do with sprouting tentacles or ovipositors, insect transformation, plant transformations, things like that. every level would be like that, centred on a theme and always making sure players want to keep going down.
...sorry, i let this get aay from me. i see something that looks fascinating and genuinely interesting, and something i haven't seen much of before, and i just spew ideas. sorry about that.
EDIT: i wrote boss as boos and you know what? that's what they are now. i no longer fight bosses, i fight boos.