@AndrewWilliamson-1240 You should consider using Azure AD Domain Services in that case. Advantage of using Azure ADDS is all the users and groups which are created in AAD will automatically be synced to Azure ADDS and you don't need to install and configure AD Connect for synchronization between these directories.
Additionally, while creating an instance of Azure AD Domain Services, you have to select/create a Virtual Network. Make sure you use the same virtual network during the deployment of WVD, so that you don't need to do any additional configuration to locate DC during WVD domain join process.
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