There are such fundamental mistakes by people who sell as "experts". The fundamental difference and basis of Islam is Tauhid.
""Say: He is Allah, the One and Only;
Allah, the Eternal, Absolute;
He begetteth not, nor is He begotten;
And there is none like unto Him.""
Quran offers a classic refutation of trinity "itself" without requiring interpretation.
The Creator, Quran says is one who created the universe! He is above the needs and causation of its creation.
"Allah! There is no god but He - the Living, The Self-subsisting, Eternal. No slumber can seize Him Nor Sleep. His are all things In the heavens and on earth. Who is there can intercede In His presence except As he permitteth? He knoweth What (appeareth to His creatures As) Before or After or Behind them. Nor shall they compass Aught of his knowledge Except as He willeth. His throne doth extend Over the heavens And on earth, and He feeleth No fatigue in guarding And preserving them, For He is the Most High. The Supreme (in glory)."
Therefore Islam offers all of humanity one submission; the Creator alone. One law; Creators. That is the only way we can free humanity from being slave of creation, other men, superstition, oppression of other laws, governments etc. One may disregard that but this is an active decision on their part.
So to those who aren't seeking truth there can't be commonality between truth and falsehood... why bother.