Both MN and CA are problematic, however, and thus any hypothesis which takes them as its givens, or starting points, will be problematic as well. The building can be no sounder than its foundation.
But Common Ancestry is not an assumption - it’s a prediction, one that has held up to repeated testing.
The GAE hypothesis, by contrast, nests within the non-negotiable boundary of CA:
I don’t think that is right can be right. A&E would not have common ancestors, and so are outside the boundary, but it is beyond the limits of genetics to know this.