You're correct. Copts are the indigenous Egyptians and they are a relatively small minority. Their language is a direct descendant of Ancient Egyptian. They're often persecuted and killed by Muslim extremists.
Copts - Wikipedia
There are many non-Copts in Egypt who also have Egyptian lineage in addition to Turkish, Arab, and sometimes European (from the times of the French and English occupation of Egypt) DNA.
There's a city called Mansoura that was especially a hotspot for the French during their occupation. Many people from the city now have blue eyes, blond hair, etc., due to their ancestors' mixing with French colonizers at the time:
Mansoura, Egypt - Wikipedia