If I need to repeat myself many times I will. I do NOT consider atheism a religion no more than I consider Theism a religion. You added a key word; the 'evolution of the concept of the church, or may be described as a 'house of worship. The atheists who are members of these congregations do function as organized churches and/or places of worship, and therefore a religion.
Just more double talk and selective semantics.
Atheism is not a religion any more than Theism is. It is a religious belief that no Gods exist. The Atheist Churches would be an example of a religion that believes in atheism.
With one side of your mouth you claim Atheism is NOT a Religion, but is a
religious belief that no God(s) exists. This would suggest that Atheist and Theistic beliefs are both religious. This is intuitively and logically flawed, since all religions are based on their religiosity which includes their beliefs. Atheism has no
religious belief components. It's like saying that birth and death is under the same heading of "life"(end of life, and beginning of life). One IS life, and the other isn't. Trying to equivocate the terms "religious belief" and "religion" is blatantly fallacious, redundant, and intellectually dishonest. All religions require a religious belief. Atheism does not, therefore, not a religious belief or a Religion. Out of the other side of your mouth, you claim that non-religious Atheists also attend, practice, and worship their non-belief in God, at Atheist churches. It is amazing this level of cognitive bias. Every biblical and literal definition of a church clearly includes "place of worship", "house or body of Christ", "place of prayer", "a religious body" or a "religious gathering". You simply ignored all of the religious trappings that defines a church, and you stop reading and interpreting after "A building or structure for public gathering..."
So, if you want to believe that Atheists worship their disbelief in the existence of a God(s), or that Atheism is a RELIGIOUS BELIEF(not a non-religious belief), or that Atheists attend Atheist churches to worship, then go ahead. No free rational thinker would barely bat an eyelid. Fortunately, most people don't need to create an entire narrative by exploiting the definition of terms, to suit whatever narrative they choose.