Create a new user in our on-premise Active Directory and fill in all required attributes.
Wait until the user is synched to Azure AD.
Connect to SfBO via PowerShell.
Run Set-CSOnlineVoiceUser -LineUri to assign him a number.
Is there any way to simplify this? Ideally SfBO should automatically pick the already assigned AD attribute telephoneNumber as the LineUri as soon as the user is synced to the cloud, without us giving more input or running further PowerShell scripts.