How can we increase the resource’s popularity?

I played it about 5 years ago, and I could reach level 7 and 15 within a week with a hero from Dungeon (using only 10 units). I also took Utopia in the second week (using undead) without any restrictions on the obelisk. But I don't spend that much time on the game, and I only need a maximum of 10 minutes per turn.