Key Christological error

All the Christological heresies partake of confusion between nature and person.

When you read the Bible and don't ignore anything, the only view of Christ that
accounts for everything is that He is BOTH God AND man.

God is both a person (someone who is God) and a nature (the divine nature).
a Person is a WHO. a Nature is a WHAT.

Jesus is God the Second Person of the Holy Trinity, God the Son, God the Logos,
from all eternity, begotten by The Father without a mother, of His essence, and is
divine. Jesus then BECAME MAN so now has the second nature of a creature
more specifically a human nature.

(The term "trinity" is not in the Bible, it is a short way of saying what IS in the Bible,
various hints and explicit statements, that give the same titles to all The Persons.
"God" is often used to refer to The Father, from Whom the other Two come, but
they come outside of time and are therefore always existing, never a time when the
Son or The Holy Spirit was not.  At Jesus' baptism, all three are present as distinct beings.
modalism is thus refuted.)

This human nature is held by Christ at the level of person not by merging it with
the divine at the level of nature. He is permanently human without losing any of His
divinity, and without the humanity being something other than human. This is a great
Mystery, don't try to fathom it.

Nestorianism separates the two natures so much that they become like two persons.
This is one confusion of person and nature. Monophysitism unites and confuses them
into one, another confusion of person and nature. miaphysitism and monotheletism
do something similar though milder enough to be close to Orthodoxy (technically
Orthodox because Trinitarian, Orthodox being the term developed in reaction to Arianism
which denied Jesus' full divinity).

Docetism (which monophysitism resembles) denies Jesus is truly physical, that this
is only an appearance not a reality. monophysitism would have His human nature
swallowed up in the ocean of His divinity so much that it might as well not exist. This
is a bit backwards, almost, because although His divinity was not swallowed up in
His humanity, it was HIDDEN in His humanity except at The Transfiguration.