For Egypt specifically, some of the most scientifically valuable additional data would come from:

Individuals from the Nile Delta and Lower Egypt, which had more direct contact with the Levant and may have higher proportions of Near Eastern-related ancestry than Middle Egypt.

Individuals from Upper Egypt and Nubia, to understand the gradient of ancestry from north to south along the Nile.

Individuals from different periods: the Middle Kingdom, the Second Intermediate Period (when the Hyksos ruled northern Egypt), the New Kingdom (when Egypt’s empire extended into the Levant and Nubia), the Third Intermediate Period, the Saite Period, and the Ptolemaic and Roman periods.

Individuals from different social strata: elite tomb owners, craftsmen, agricultural workers, soldiers.