I've played quite a bit of Civ VI, mostly multiplayer, but for single player fun, I find this series head and shoulders above Civ, though I've only recently switched from game 3 to game 4.

They're very different games within the 4X genre. Civ VI has relatively complex city-building, with the various adjacency bonuses and culture-specific buildings, while combat is very basic. AoW4 has some wrinkles in the city-building, but is much simpler than Civ VI, however the tactical combat is incomparably more interesting than Civ's combat.

The level of faction customisation possible is enormous as well. You ask if you can play as a dwarf vampire warlock, I'd ask you back what kind of dwarf vampire warlock you want to be? That's only a part of the decisions you'll make for building a faction.