Arianism, Nestorianism, and Modalism exist only in the imaginations of deeply lost Creature worshipers (read:pagans).
Either Jesus is God or He is not God.
"Jesus is God" is the Christian belief.
"Jesus is not God" is the belief of Arians (among others).
"The Son truly became Man" is the Christian belief.
"The Son did NOT truly become Man" is the belief of Nestorians (among others).
"The Father and The Son and The Holy Spirit are distinct persons" is the Christian belief.
"Father, Son, and Holy Spirit are different ways that God interacts with creation" is a the belief of Modalists.
The errors of Arianism, Nestorianism, and Modalism exist in the real world; they are not figments of anyone's imagination.