@Ethan Trigg Thanks for posting in our Q&A.
To avoid any misunderstanding, could you please tell us that you want to have both On-Prem AD and Azure AD or you only want to have Azure AD?
If you want to have both On-Prem AD and Azure AD, the device is a hybrid Azure AD joined device. For hybrid Azure AD joined device, we only can use domain user to sign in.
If there is anything misunderstanding, please correct me.
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