Spooky_Lairs is a lora for making lairs filled with webs and bones and candles. It can do "underground" caves(It knows stalactites, although alas, not stalagmites), and partially open buildings, as well as more ritual areas.
It can be a bit hit and miss - YMMV - but it does work well with most loras I've tried, which might mean it does a good background for you, while your other loras and prompts build the foreground focus.