Well, let us play that through
- Register on microsoft.com for an account
- pay for your personal office 365 subscription.
Where you will have access with Azure AD with that?
There must be a reason lots of other services which support outlook.com/personal accounts and work or school (organizational accounts) provide two separate connectors, including MS own solution.
You won’t have a domain or Azure AD access by the time you registered and paid a personal or family subscription from what I know.
Sure, Azure AD has a free license and is included into a business subscriptions. But even the basic business subscription differes hugely from the personal or family subscriptions (by functionality and price.)