Blizzard has added the Great Vault icon to the Valdrakken map on the Beta and temporarily removed the requirements in preparation for the weekly chest update in Dragonflight.
The Great Vault is now visible on the map of Valdrakken, making it difficult to miss. It is located in the banking area of the new city.
The Great Vault requirements have been removed on the Dragonflight Beta, suggesting they may be updated for the new expansion as soon as this week.