That's not the same thing, though. Gullah refers to the people in the coastal and sea island areas .
Arriving to this country through the ports in that region (BEFORE 1808) is not the same thing as being Gullah or being descended from those folks.
That group of folks lived in relative isolation on the coasts and sea islands, which is partially why they were able to retain so much of their heritage(s). Also...when the international slave trade was abolished.....I'd imagine that out of the the enslaved Africans who were smuggled in after that, that some ended up there which replenished the African cultures being blended there.
Your dna tests show that connection, but it's a stretch to say that majority of Black folks in America are related to the Gullah people.
Because of location, I believe that Au Cap (Cap Haitien) (formerly Cap Francios) was the busiest arrival port for Africans in what is now Haiti.
Because of the nature of the slave trade, and people being moved around.....in an
area a fraction the size of what the US was in 1808., how likely is it that majority of Haitians would be be directly related to people from Au Cap region.
What you're writing doesn't seem to add up.