Gib Primogeniture’n Peace
This mod allows you to select Primogeniture without having the Late Feudalism Administration Law. It also makes it possible to go to any Vassal War Law regardless of the Administration Law you have. So you can finally play tall without having your small vassal Willy "the ambitious" conquering half of the world while still being a king.
Please, if you’ve liked the mod rate it up! 😀