You're actually right there, it's the oldest heresy. But you know what I meant.It hasn't been missed for two thousand years.
Christian orthodoxy has always maintained that the trinity in no way compromises God's one being. We are strict monotheists regardless of how much you kick and scream that we 'just don't understand' the Scriptures. The mere existence of non-trinitarians doesn't invalidate the doctrine as held by the majority thought history.There are also obviously Christian groups today that also recognize that God is ONE, - no trinity, - no Jesus as God.
And so you claim, and so we reject. Saying something over and over doesn't make you right.And as has been pointed out over and over - there is no trinity doctrine in the Bible, nor does Jesus say he is God.
You seem to think that just because a word isn't explicitly spelled out, the concept isn't there. We disagree. The Church and the majority of the Christian body disagrees. But of course, only those who agree with you have a valid understanding of the Scriptures.