It is true, I had some of those examples in mind when I said that. Those are all relatively newish and American (except the unification church). And Scientology isn't a Christian denomination. I was also thinking of denominations that teach it but don't consider it foundational. East Orthodox, Catholics, Orthodox Coptics, the African Orthodox Church... these might mention it but usually will not say that is the characteristic that defines Christians (results may vary by church). Christians are followers of Christ Jesus, and he never said you need to think about God as a Trinity. Even if you believe in the Trinity, you know that it represents one God, so the claims of heresy/polytheism are based on a misunderstanding.

I think you know that answer. Cults have spurious doctrines, they are built on the theology/experiences of one person (Joseph Smith, Charles Take Russell, Mary Baker Eddy, L. Ron Hubbard, etc.), they create their own holy books to justify their own distortions of the Bible (New World Translation, Book of Mormon, Science and Health, etc.).

How come they are in a cult and you are in a denomination?

I was challenged by your statement to come up with ANY Christian denominations that don't teach the Trinity, let alone MANY. On this site I came across (https://www.learnreligions.com/faith-groups-that-reject-trinity-doctrine-700367) , all the listing are cults, not Christian denominations. So you'll have to tell me about these "many" "denominations" that don't teach it at all. In what Christian world is the Trinity not core doctrine?

Trinitarianism doesn't define Christianity. Many denominations don't teach it at all. To me, it's just one of many ways to picture something incomprehensible. It shouldn't be considered heresy or a requirement for faith.

Of course He did. But where does the text say that God was "fully revealed" in the Torah? As we trace God's revelation of Himself to Abraham, we see separate theophanies, each with a different kind of revelation (Gn. 12: voice; Gn. 12: protection; Gn. 13: through Melchizedek; Gn. 15: in a vision; Gn. 17 by covenant; Gn. 22 by challenge). Which of these claims to be "full revelation"? And is there nothing more that God can reveal to Abraham?

Same with Moses. We see many theophanies, each with a different kind of revelation (burning bush; miracles; Sinai, etc.). But we still don't have a full revelation. God reveals more to David later. He reveals more to Isaiah later.

I'm still challenging you to substantiate your claim that God was fully revealed in the Torah and that there is nothing left to be revealed.

Didn't God revealed to Abraham and Moses?

I don't dismiss the 1st five books at all. Where is the text where it shows that God was "fully revealed" in the Torah?

For Jews, God was fully revealed in the Torah (the first five books of the Old Testament).

You dissmis the first five books?

No. Christians worship a trinitarian God, which is heresy in both Judaism and Islam.