We had the same issue with a native AAD device. Stopped at Security Policies (Identifyting) for a long time (15-20min). We still have an open ticket with MS about it, but our hypothesis is that it has to do with the schedule tasks not running due to the time being incorrect/changing during autopilot. One thing you can try is what is noted on the Autopilot known issues thread:

• Boot the device to the start of the out-of-box experience (OOBE).
• Establish a network connection (wired or wireless).
• Run the command w32tm /resync /force to sync the time with the default time server (time.windows.com).
• From: https://docs.microsoft.com/en-us/windows/deployment/windows-autopilot/known-issues