In Another World, I Must Train my Dungeon: A LitRPG Adventure by Miles English
The second book, building on the first.
Henry comes back to town, from working on a ranch. (He was really impressed by what the other hands, all Level 1, could do to manage an enormous cow with nothing but a lasso.) Daniel is having trouble with magic. Their dungeon, the title dungeon, is not growing.
The Circle of Diamonds, another of this world's factions, acts against them; Daniel ends up prisoner. And Henry talks to his father about their problems, and they work on the dungeon. Nigel gets involved from his restaurant. It involves immigrants, finishing something by dawn, classes and whether they should acquire them, letting a guy escape, and more.