If you are on a PC and the option is "greyed out" in your settings, you likely need to manually trigger the download through your storefront:
The Ultimate Guide to the Enhanced Graphics Pack DLC for Age of Empires II: Definitive Edition enhanced graphics pack dlc age of empires 2 exclusive
The Enhanced Graphics Pack DLC is a downloadable content (DLC) package designed specifically for Age of Empires 2: HD Edition. This DLC was created to enhance the game's graphics, making it look more visually appealing and immersive for players. The pack was developed in collaboration with Forgotten Empires, the game's modding community, and Microsoft. If you are on a PC and the
A: No. It is free on Steam. The "exclusive" label refers to platform availability. the game's modding community