You seem to be more vague as we go along here. Want to start over?
You brought up the, unsupported by Genesis IMO, notion that Noah was special not because he was a righteous man of faith, but because he and his sons were the only surviving humans not “polluted” by demonic/Nephilim blood. And that the reason for this was an attempt to destroy the bloodline necessary to produce Christ, or perhaps more accurately, Mary.
To document this I pointed out that in the two reported lines of Christ’s ancestry, there are a significant number of known non-Israelite women. With the reasonable assumption there are a bunch more in his millions of other ancestors in the thousand years between David and Mary.
IMO God does not obsess about bloodlines, since there are multiple examples of faith being the critical issue for him.
Hebrews 11: By faith Noah, when warned about things not yet seen, in holy fear built an ark to save his family. By his faith he condemned the world and became heir of the righteousness that is in keeping with faith.
No mention here at all of his bloodline.
So who do you think the “polluted people” descended from the Nephilim were in ancient days and today? And how did the Nephilim survive the flood?