A big problem is that atheism often gets popularly conflated with scientism (and one atheist philosopher even
wrote a much criticized book contending that scientism was indeed the proper thought orientation for such). Scientism pretty much rules out any kind of exo-Abrahamic, Eastern or non-Western mysticism slash spirituality as an alternative, too.
But since gods were ultimately just concepts, principles, laws, values, aspects of life/death, and worldly patterns/cycles that were personified... The community of non-theism actually still wallows in and is regulated by such invented ideas slash useful fictions, too -- compliance and commitment to them, even a kind of reverence in terms of political and cultural canon. The difference is that it stops short of the religious anthropomorphism and zoomorphism of those abstractions.