I had that setup already, then removed the Device Registration one as I was advised that this was NOT needed for Hybrid Azure AD Join, as all domain devices register as Hybrid Azure AD Join once AADC has been configured this way.
I had that setup already, then removed the Device Registration one as I was advised that this was NOT needed for Hybrid Azure AD Join, as all domain devices register as Hybrid Azure AD Join once AADC has been configured this way.