Atheism is the position that there are no gods. That position is a claim.
Organized, or disorganized religion is still religion. Most of the time it does center around belief in a god, gods, spirits, souls etc… If it involves a belief in a god or gods…its religion. It doesn’t matter to me if its organized or disorganized, or unaffiliated or whatever.
Religion without a deity is probably more accurately a philosophy. Buddhism comes to mind, although I believe there is theistic buddhism. Jainism comes close, as there is no belief in a god or gods as a creator(s). They do believe in rebirth, and the soul, also in captive and liberated souls.