@Jayd , For the error code “80070774” , it can mean a few different things. like “Intune never found a domain join policy” and “Intune failed to create a device object.” We can check out the ODJ Connector event log to see if there was even a request received.
In addition, for Windows Autopilot user-driven Hybrid Azure AD Join over the internet using a VPN, we can refer to the following links:
https://oofhours.com/2020/06/23/windows-autopilot-user-driven-hybrid-azure-ad-join-over-the-internet-using-a-vpn/
https://www.peters.com/blog/whats-new-with-autopilot-hybrid-azure-ad-join-over-vpn/
https://oofhours.com/2020/07/19/troubleshooting-windows-autopilot-hybrid-azure-ad-join/
Note: Non-Microsoft link, just for the reference.
Hope it can help.
If the response is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.