Once you go back beyond 6,000 years, and especially 10,000 years, what’s the point of trying to prove a bottleneck “older than 10,000 years, and hidden in a shadow”?
If it creates a motivation for YEC’s to preserve their position in an Old Earth Scenario… good… .let them work for that.
Our job has been to show that the “Young Earth” part of any Christian’s world view is untenable. The more YEC’s work to legitimize an Old Earth Scenario, the better it will be for everyone!