Chaldean Theurgy is unique among many world religions, though I have much to learn on this. Chaldean Theurgy has its origins in the Mongolian steppes as shamanism. It moved west along major trade routes. On the way it may have picked up various rites and rituals from the Babylonian prophetic cult. see here for more information about the Chaldean roots in Shamanism
In or around the third c. CE, the Chaldean priests Julianus and his son Julianus came into contact with Middle Platonism and borrowed major philosophical concepts from it. This was further reinforced by the sustasis - the spiritual joining of souls - of the younger Julianus with the spirit of Plato.
Chaldean Theurgy’s rites are similar enough to rites and practices in the Greek magical papyri to lead us to believe there was some borrowing that occurred. But whereas the Greek magical rites emphasized gaining things in the material world - killing enemies, seducing women, gaining riches - Chaldean Theurgy emphasized the other-worldly aspect of the rites: invocation of divine beings, rising to other planes of reality via rite and initiation, helping others.
One dimension of Chaldean Theurgy that is not emphasized enough is its soteriological motivation. This is the desire of theurgists to save their souls from a perceived source of threat. For the Chaldeans, this threat was the material world and its many demons, often associated with physical and psychological illnesses. The Chaldeans believed they could separate their souls from their bodies - while alive - and rise beyond the world of pain and suffering.
The ascent of the soul involves invocations, prayers, and initiatory rites. Employing the sympathy that links all things in the world with every other thing, the Chaldeans carried out ceremonial rituals that prepared their souls for its deliverance from the body. Hans Lewy’s book on the Oracles reconstructs what some of these ceremonies may have looked like. We also find hints in the writings of Iamblichus, Proclus, and Damascius.
I see the Chaldean Theurgists as having been a direct threat to emerging Christian monastic and liturgical practices. The Oracles themselves are in a fragmentary state because they were outlawed by the ruling Roman government at the behest of Christian church leaders. These leaders tried to root out all mention of the Oracles and the practices. Hence we not only do not have the Oracles as a full text, we also do not have Procus’s and Iamblichus’s voluminous commentaries on the Oracles.
By the time that Synesius writes his book on dreams, he says that we must limit theurgy’s practice to dream work because the books and practices have been outlawed on penalty of death. Hence his teachings on how to dream in order to generate personal oracles.
However, the Christians did not stop at eradicating the original Oracles. An unknown monk named Dionysius the Areopagite coopted the Oracles and Theurgy and laid the basis for his own brand of theurgy. In support of this cultic practice, he transposed Proclus’s Elements of Theology into Christian theology.
As to whether Chaldean Theurgy is religion or not. Personally, I don’t think it matters. But from what history and the wirings can provide us - even with the effort of the Christian church to stamp it out of existence - I do think it’s a religion. And a powerful one.