There are some super exciting palaces in Skyrim, such as Blue Palace or Palace of the Kings. But as soon as you arrive there they turn out to be rather empty, and honestly, underwhelming. Well, the PCE mod changes that.
It offers a complete interior re-design of the six major castles in Skyrim SE, including Dragonsreach, Blue Palace, Castle Dour, Mistveil Keep, Understone Keep, and Palace of the Kings. There you will meet new NPCs, take on new quests, and discover some surprising secrets, too.