As a monotheist I think there is only one God so there cannot be multiple Gods
The tenets of the majority of the formalised expressions of your religion count three distinct bodies formally dubbed as 'gods' - Father, Son, Holy Spirit, to give one expression of them. Then there are the wealth of other supernatural beings considered to be part of the 'hierarchy' (i.e angels) which are somewhat arbitrarily considered not to be of a similar ilk. Then there are the wealth of other gods from the original pantheon your deity comes from in antiquity. You might claim to be a monotheist, I have no reason to doubt that you genuinely believe that there is only one god, but that doesn't appear to mesh with the Christian doctrine (which also, in defiance of the evidence, claims to be monotheist as I understand it).
Although there may be three persons there is only one God, it's a bit like thinking that Ice , Water and steam are all H20.
So 'god' is what, a quality? A material from which these beings are constructed? A piece of ice is not the entirety of water, so is 'The Father' all of God? The important thing about the states of matter is that one example - one accumulation of the material - cannot be in multiple states at once. You can have something that's water at one point in time and undergoes a transformation to ice or steam or potentially even plasma or a few others. But it's not both steam and water at the same time: I understand (and correct me if I'm wrong) that the Christian depiction is that the Father and the Holy Spirit are both god at the same time?
I reject that definition as applying to the trinity
Oh, you reject it. OK, that's fine. Well then I reject your rejection, no backsies! Why do you reject it? What, functionally, materially, fundamentally, is the difference in nature between, say, Jesus and Lucifer?
The problem with the polytheism's Christianity has historically encountered in the west is that the nature of the gods can be described as superhuman rather than the abrahamic view of the one being the creator and judge of all.
Not really. Most pantheons have a creator figure, in Christianity it's the Logos - in the beginning there was the Word. Many have a judge of the dead - Rhadamanthys, Minos and Aiakos in Greek myth, Ma'at in Egypt, Yama in Hinduism, Hel in Norse mythology... In the Canaanite pantheon from which Yahweh emerged, El was considered the creator deity, I'm not sure if we know enough about them to know if they had a concept of judging souls at that stage, or if their deities were not still primarily tribal.
The story of christianity is the harmony of the persons of the Godhead above the drama of humanity.
The Christian depiction of the Story of Christianity, perhaps. The history of Christianity is somewhat different.
The various pantheons do not have a Godhead but rather a head god who is not just an arbiter in the struggles and intrigues of lesser gods but is joyfully involved in them.
They have a concept of divinity that is shared - and diluted - amongst various levels of supernatural beings, which is a similar situation to the Christian Holy Trinity (Zeus, Hades and Poseidon, say), the archangels (the lesser deities), the saints and angelic offspring like Nepheliem (demi-gods)...
O.