I don't think so. Calvinism has God denying essential changing, regenerating grace to those He does not choose to elect. The onus is then on God.
The Truth is that God gives each of us sufficient grace to become "saved." The onus is on us to respond.
Trinitarian doctrine was not always accepted in the Churh.
True. Until the 4th century, then it became defined dogma. Which is not to say there were not dissenters about.
If knowledge of the entire, complete truth of God is required, we are all damned because no one has it ALL right all the time.
Absolutely. But the definition of the Trinity is a far cry from "the entire, complete truth of God."
SD