An atheist is someone who thinks theism is false. It doesn't entail mysticism or anything like that. Most Western atheists, though, are naturalists, skeptics, and humanists, and I've developed an atheistic worldview in my writings that combines pantheism, existentialism, pragmatism, transhumanism, and other ideas. My recent article on atheism goes over the pejorative connotations and the word's historical origin (link below).
I agree there's an inner struggle that's evident from my writings. I call it the struggle of remaining existentially authentic. You can see it also in the friction between counterculture and mainstream culture (which I write about). For instance, on Medium there's the conflict between trying to sell out and remaining artistically pure. Or there's the conflict between being social and therefore fake, and keeping in mind the alienating truths about our species' position in nature.
Most great artists struggle for these basic, existential reasons. The struggle's fuel for art that redeems when knowledge condemns (as my Medium motto says). So, no apologies for struggling with the human existential condition.