Well, I'm not a geneticist, so don't shoot me. Then again, neither is "Mathilda", the student-writer of that "anthropology blog" you linked. Take a look at the tab "About me and my blog", where she questions the "out of Africa" theory of human evolution, argues that race is a biological reality, that people label her as racist and dedicates a paragraph to "afrocentrists" and how she "enjoys irritating them now". She is neither an expert in DNA, nor African history, let alone ancient Sudanese DNA and history. Her writing seems to be quite reactionary and biased.

A few pointers:

The question of Kushite ethnicity has been a highly controversial subject since the earliest modern explorations of Nubia by archaeologists like John Garstang and George Andrew Reisner. These men performed some of the earliest, and some of the largest scale excavations of Kushite archaeological sites to date. Sites like Gebel Barkal and Meroë. They're essentially giants in Nubian archaeology. They were also heavily influenced by scientific racism, and by virtue of the advanced nature of the civilization they were uncovering, ascribed the ruins to an imagined light skinned Libyan dynasty, as Dr. Timothy Kendall put it, "using entirely specious evidence". This unfortunate legacy has continued to dog Nubian studies ever since, with many studies being presented or misrepresented to fit one view or the other e.g. Kushites were black Africans closely related to Sub-Saharan populations vs Kushites were actually light-skinned Euro-asiatics more closely related to Mediterranean populations.

The argument is very similar to the debate about Ancient Egyptian ethnicity, and often seems to have more to do with 21st century race politics in America than with actual science.

This question doesn't have a straightforward answer, so here I go:

Yes, there is "Eurasian" DNA in ancient Sudanese populations, and this Eurasian DNA is also present in the modern populations of Sudan. Eurasian doesn't mean European though, at least not in this case. It refers to ancient back migration of Asiatic populations that eventually diffused into Europe as well as Africa. In fact, Eurasian DNA can be found in a large variety of African populations, especially in horn of Africa populations like the Amhara, the Oromo, the Somali, the Afar, but also in some West African populations like the Fulani, the Hausa and the Yoruba, and East Africans like the Swahili, the Kikuyu, the Maasai and the Malagasy. Even the Khoisan of Southern Africa have significant Eurasian DNA... So you see, the term "Eurasian" is a little misleading here. It's a back migration of Asian DNA into Africa. Similar to the Asian DNA that crossed into Europe. Of course there was also actual European migration into Africa, mostly on the North-African coast, adding to the genome of the Berbers and the Fulani, for example. The Eurasian admixture to Khoisan DNA was estimated at c. 3000 years ago. As for the back migration into North and East Africa, we're looking at a date of approximately 30.000 to 14.000 years ago. This is a Pre-Historic event predating even the Neolithic revolution.

Unlike what the the study implies, this Eurasian ancestry in Kushites is not some kind of marker of their non-Africanness. At all...

As for the question of skin-colour, "Eurasian" is not synonymous with white, or "Europoid". In fact, the Eurasian back migration that contributed to the DNA of Kushites happened before light skin tones were even widespread, anywhere.

Another important note to take into account with these kind of genetic studies is that their scope is always very, very limited, and the exact origin and context of the samples isn't always clear. This is important because:

Kush was a very diverse, multi-ethnic state. Just like Egypt, Kush wasn't an ethnic monolith. Many, many, tribes inhabited the area. Northern Kushites (Lower Nubia) had much in common with Southern Egyptians (Upper Egypt). Northern Egyptians on the other hand had much in common with Levantine and Libyan populations, while Southern Kushites had more in common with Nilo Saharan populations like the Nuba. There would have been a gradient, North to South, where the populations on the border with Egypt would have been, in very general terms, lighter skinned than the people living in Meroë or further South. Just like today. In fact, a number of studies show that the modern population of Sudan is very close in ethnic composition to the ancient Kushites. Modern Sudanese, like the ancient Kushites would have been, are a very diverse bunch, with skin-tones ranging from jet-black, to yellowish brown.

Although colored frescos from ancient Kush are exceedingly rare, there are significant numbers of depictions of the Kushites by themselves in the reliefs of Begrawiya, Naqa, Gebel Barkal etc, as well as royal statues which often clearly show Sub-Saharan features. In fact, Meroitic period Kush is known for the more explicit Sub-Saharan features in their art, but rulers as early the 25th Dynasty Taharqa are repeatedly depicted as "Negroes". Some reliefs and statues also depict more Afro-Asiatic features (with aquiline noses, for example), more prevalent in the northern areas. Ancient Egyptians invariably depicted them as either jet-black or brown. There is also a rich corpus of depictions of Sub-Saharan Africans in Mediterranean art, particularly Greek and Roman, almost certainly depicting Kushites.

Long story short, yes they have "Eurasian" genetic admixture, but that doesn't mean they weren't black, or less African than any of the many other major African populations, many of whom have Eurasian DNA themselves. Of all people, they would have looked most like modern Sudanese, in all their glorious diversity.

Eitherway, skin-tone would have been utterly irrelevant to Kushites (and Egyptians alike), and they would have judged you based on the gods you worship, not your color.