If there is no Virgin Birth, there can be no Incarnation
If there is no Incarnation, there can be no God-man
If there is no God-man, there can be no Atonement, for
There is none with humanity to shed blood and Deity for Efficacy
If there is no Atonement, there is no salvation and all are Yet in sin

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Considering this I have myself concluded that the "belief" of the virgin birth of Christ is the
"sin "factor.

Christ most certainly has taken sin from those that believe. Some of the scripture I love the most.

Luke 1:77  To give knowledge of salvation unto his people by the remission of their sins,
Acts 10:43  To him give all the prophets witness, that through his name whosoever believeth in him shall receive remission of sins.

Now that idealism would not stop those that don't believe in the virgin birth to be "saved'. It is only an indication of whether it has yet happened in that life.

Is anything too hard for God?

For each salvation there is a season.

I doubt that anyone can be fully saved and not realize this.