Anarchy and atheism are very different things. Some anarchist may be atheist and some atheist may be anarchist. You might do better seeking an anarchist website.

Atheism is a lack of belief in even one deity. Definitionally, you are either a "complete" atheist, or you're not an atheist at all. It has nothing to do with politics.

Now ... if you're an atheist and are interested in anarchy, then start a group here on the topic. Although if you're looking to make an echo chamber rather than expose yourself to honest debate, you can do that ... but it won't be a very credible effort.

Good luck!