As far as I know, there isn't a Cabinda flag. Those flags one can find actually pertain to certain to those secessionist movement. So I decided to create a flag that represents Cabinda uniqueness, but as neutral as I could.
My inspiration for this flag is the Monument of Simulambuco, located where the treaty of same name, incorporating Cabinda as a then-Portuguese Crown's protectorate.

The three spears in front of it represent the kingdoms of Kakongo, Loango, and N'Goyo. I incorpotated them in the flag, but in a different way:

The blue color represents the Atlantic Ocean. The design could be mirrored, if one prefer:

I like the visual experiment with the arrows. The result is surely striking.
Comments and suggestions are welcome.
Sorry for the delay, again.