Does not shut down

This sounds like a Windows issue, not a machine issue - check the logs for errors in Computer manager and see if you can find a matched log, otherwise recreate it and note when it occurred to trace it down - You want to look for an error like this:

To get to Computer management, right click on the start menu here, or search for it:

Look for these errors:

• Kernel-Power (Event ID 41): Indicates the system rebooted without cleanly shutting down first.
• Power-Troubleshooter: Shows what triggered the last wake-up or restart.

As soon as you have log files, come back and we'll see what we can find out. I have both the 640 and 645 (0=Intel, 5=AMD) and neither of mine have had an issue with this from a blank install from the MCT. These use modern sleep S0 (but it behaves mostly like S3 classic sleep), whereas the newer NPU 6/8 series (I only have a G1a, so can't speak on the G1i or G1q) are all in on modern S0. I forced it on my G1a unit in command prompt, but it was very much hidden on the Ryzen AI unit until I made it play nice with the powercfg CLI commands.

There are a few things you can try if the error cause is unclear:

Disable the Intel ME power management ("Allow the computer to turn off this device to save power"):

1. Go to Device Manager.
2. Find Intel(R) Management Engine Interface.
3. Right-click Properties > Power Management.
4. Uncheck "Allow the computer to turn off this device to save power".

Force S3 hibernate with CLI: