Were scientists in Ancient Egypt Egyptian, or were they from other regions?

There are no historical records, that I am aware of, which explicitly refer to any individual Scientists within PRE-Alexandrian, Ancient Egypt.

This does not automatically exclude the possibility of Archaeologists discovering evidence which specifically refers to individual ethnic Egyptian Scientists. However, at this point in time, there are no Ancient Egyptian Scientists to speak of.

Consider the flourishing of the New Kingdom:

The New Kingdom of Egypt, also referred to as the Egyptian Empire, is the period in ancient Egyptian history between the 16th century BC and the 11th century BC, covering the Eighteenth, Nineteenth, and Twentieth Dynasties of Egypt. The New Kingdom followed the Second Intermediate Period and was succeeded by the Third Intermediate Period. It was Egypt’s most prosperous time and marked the peak of its power. [Wikipedia - New Kingdom of Egypt]

The rise of the New Kingdom was immediately preceded by the rule of The Hyksos:

The Hyksos... "foreign rulers" ... were a mixed people from West Asia who took over the eastern Nile Delta , ending the thirteenth dynasty, and initiating the Second Intermediate Period of Ancient Egypt.[Wikipedia - Hyksos]

i.e. The Hyksos were not Egyptians. See: Modern scholarship usually assumes that the Hyksos were likely Semites who came from the Levant.

Concerning the period of Hyksos rule, Egypt made many technological advances:

The Hyksos brought several technical improvements to Egypt, as well as cultural impulses such as new musical instruments and foreign loan words. The changes introduced include new techniques of bronze working and pottery, new breeds of animals, and new crops. In warfare, they introduced the horse and chariot, the composite bow, improved battle axes, and advanced fortification techniques. [Wikipedia - Hyksos]

Further, here is a writer who directly connects the rise of the New Kingdom to Hysos innovations:

However, the presence of the Hyksos was not entirely negative for Egypt. They introduced Egypt to Bronze Age technology by teaching the Egyptians how to make bronze for use in new agricultural tools and weapons. More significantly, the Hyksos introduced new aspects of warfare to Egypt, including the horse-drawn war chariot, a heavier sword, and the compound bow. Eventually, a new line of pharaohs—the eighteenth dynasty—made use of the new weapons to throw off Hyksos domination, reunite Egypt, establish the New Kingdom (c. 1567-1085 b.c.e.), and launch the Egyptians along a new militaristic and imperialistic path. During the period of the New Kingdom, Egypt became the most powerful state in the Middle East

Arguably, the zenith of Egyptian power and success, the New Kingdom period, was to a large extent the result of those innovations introduced by the Hyksos. If so, although we may not be able single out particular individuals who were or were not Egyptian, we can make a reasonable assertion that the flourishing of ancient Egyptian culture, exemplified by the New Kingdom period, was the result of the non-Egyptian science and technology introduced by the Hyksos.

Disclaimer: I am by no means an Egyptologist, and I'm quite certain I've merely scratched the surface of a subject that has been discussed in far more depth in scholarly literature.

(An interesting aside concerning the Hyksos: For those seeking extra-biblical support for the presence of the ancient Hebrews in Egypt, see: The Hyksos continued to play a role in Egyptian literature:

The Hyksos continued to play a role in Egyptian literature as a synonym for "Asiatic" down to Hellenistic times...and this may have led the Egyptian priest and historian Manetho to identify the coming of the Hyksos with the sojourn in Egypt of Joseph and his brothers, and led to some authors identifying the expulsion of the Hyksos with the Exodus.

However, I believe that modern scholars have found little support for this claim.)

Science is a modern concept, "a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions".

Although the ideas of science came gradually, and it is not possible to point out a single moment when science was born, the first real science and the first real scientists are usually attributed to the 15th to 17th century, and the scientific revolution.

In ancient Egypt there was for example no difference between medicine and magic. The famous architect, engineer and physician Imenhotep (probably) wrote a medical text that is well known for being very practical and having very little magic in it. But it too contains magical spells, showing that Imenhotep also did not adopt a wholly scientific attitude. Instead the text is probably low on magic because most of the ailments it is concerned with are external. Much of it deals with trauma, and it is probable that it was a text book rising out of, and used in, battle-field medicine.

So there were no scientists in ancient Egypt.