Naval warfare in a single player game?

Maybe I’m missing something, but why are there so few (4) single player campaigns and why don’t any have water? It also appears there is no way to create a map with water in single player (vs AI) skirmish mode, or perhaps at all! Is this feature disabled on the Game Pass version?

Sea warfare wasnt very common in the Medieval era, maintaining ships, especially for warfare is very expensive for a non centralised government. And there are two water maps you can choose, warring islands and another one I cant remember the name for.