AoE2 and the United Netherlands and Spanish Netherlands? nope. This is way too late in timeframe.
During the Romans there were Frisians, Batavians, Cananefati, Saxons. And Belgium had other tribes.
In the early medieval times the Frankish Middle Kingdom was owner of the Netherlands, mostly the central area. The North was free those were the Frisian tribes and their Chieftains, the āFrisian Freedomā existed during this time. During this time the Frisians existed as traders and vikings. Hence theyāre also known as the Frisian Vikings.
The Danes also took over the Netherlands in the early medieval times for about 80 years if i remember correctly.
Before the Hanseatic there formed counties and duchies. Holland and Zeeland in the west. Utrecht was the local Vatican ruled by a prince bishop and the canons of the church. In the south there were the Brabants, a belgian people. In the east the Gelder which are more connected with germany. And in the north the Frisians and some trading cities like Groningen, Zwolle and Kampen. Some aligned more with the Danes because of closer ties with the Hanseatic league. Thus the north was more oriented on Scandinavia and Germany.
Then the Burgundians arrived in Belgium and slowly took over. And expanded their influence to the south (Brabant), Zeeland and Holland. These factions can be described as our current civilization Burgundians.
In the center continued the Prince-Bishopry of Utrecht, it had a civil revolution backed by the Holy Roman Empire and granted the city its cityrights. It also colonized the northeast and tried to conquer the north. And had wars with Gelder in the east/southeast. Meanwhile the Frisians fought off invasions from Munster and Saxony.
As of today Utrecht still has a castle of the Teutonic Order. Gelder is different, together with regions more to the north they have a more Saxon culture. Hence i think Saxon would be a good sub-civilizations to add. Because theyāre also in Germany.
For the Netherlands i would say Saxons and Frisians are options to represent them more. Because we already have Burgundy, Vikings and Teutons.
But we also have Franks and they cover us too. Because we were invaded by the Franks. And the unique unit is throwing axemen which were also used here by the local nobility throughout the dutch Netherlands.
Maybe for Germany there could be added the Palatinate, Saxons.
For southern germany, swiss and austrai there could be added a combined civ that is based on Bavarian culture.
For the north of Germany we have the vikings and my earlier adding the Frisians. And for Mecklenburg-for-Pommern the former west slavic area we already have the Poles.