What do you mean? It's just that. Following the reincarnation of a jaded stubborn atheist trying to survive in alternate reality during WW1. The big picture is about the relationship with her and "Being X" that she totally refuses to acknowledge as the
supreme being. So far they haven't done much with it and the recap episode 6.5 didn't really bring it up either. From this point I'd say the manga is way better at explaining this point of the story, it's probably a no-brainer.
The anime so far is Tanya avoiding death, but she's reckless and brutal from the word "go". There's not really an arc to her, he was a cunt in his past life and she still is now.