@Dave Baker ,
To set up a WVD/AVD environment, you need to have an Azure AD or Windows AD in sync with Azure AD, or An Azure subscription parenting to the same Azure AD tenant, and a list of host OS supported by Azure. You can also use Microsoft Intune to manage Windows 10 or Windows 11 Enterprise multi-session remote desktops in the Microsoft Endpoint Manager admin center just as you can manage a shared Windows 10 or Windows 11 client device. I can't understand the correlation between AVD and Office 365 licenses. If your intent is to use the office apps on the virtual desktop then the logged-in user should have the O365 subscription.
Hope this helps.