After Canaan was cursed...the next time you hear about him is when Joshua & Caleb go to his land in Numbers. They were afraid because of the sight of the Nephilim...that dwelled in the land.
Putting two and two together with how the Nephilim are described in Noah's time and with the Curse of Canaan having Nephilim in his land...these are his descendants that were cursed. The Neanderthal DNA is what changed the original black people of Canaan into the Nephilim.
Breh, you're making connections where there aren't any. For one, the argument falls apart at the Canaan was cursed doctrine. Because
1) Canaan himself was cursed, not his descendants. To say oherwise is reading into the scriptures.
2) Noah stated Canaan would be cursed out of anger, not the Most High. Who is Noah to really 'curse' anyone?
3) Even if there was a curse on Canaan, it was to be a servant, not that he was somehow a wicked seed or anything else.
4) Canaan's descendants occupied what would later be called Israel and flourished. Doesn't exactly sound like they were cursed in any way.
But even if we ignore these points, them being scared of Canaanites (not Nephilim) doesn't exactly prove your point at all that they were white people.