I'm guessing that region of the map hasn't had much love yet. The focus of the last update was Anatolian/Thracian/Hellenic units. I suspect Nubian archers will make an appearance in a layer update.

The devs mentioned the unit rosters are an ongoing work in progress, some of them are more placeholders.

Got it thank you so much. It can be so difficult to find out information from ongoing mod development

As Dahoota said. Only The Hellenistic units have been remade. For more info about mod progress join our discord. :)