Hello greenkeys,

Welcome to Lenovo Community

I'm sorry that you're having facial recognition issues

I suggest that you go to BIOS, load default settings then save and exit.
Have you also checked for the latest BIOS update from the support site?

Update us how it goes

Regards, 
Lorenzo_Lenovo

Hi greenkeys,

Welcome to the Community Forums.

If what Lorenzo suggest doesn't help, then I'd try to roll back the update or use a System Restore Point to set the device back to a state where it was working, while also disabling the Automatic hardware driver updates. In the even this doesn't help solve the issue, then there's a witch hunt in trying to figure out where the incompatible drivers from the Win 20H2 update are and what the incompatibility is, so a system recovery/reset is the best course of action in this case:

Step 1. Rolling back to a previous Win 10 Version :
- Open the Windows 10 Settings Menu by clicking the gear icon in the Windows Start menu, or by pressing “Windows+I” keys.
- Click “Update & security”
- Click the “Recovery” tab on the sidebar.
- Under “Go back to the previous version of Windows 10,” click “Get started.”
- After some elapsed time after last update(10+ days), this option is often not available. Please continue below.

Step 1.2. System Restore Point
- There should always be a "restore point" you can choose from "System Recovery"
- Click the Windows key and type "System Recovery" and click "Recovery" in the list.  
- Select "Open System Restore" - Click "Next" and select the latest "Restore point" where the device was working.
**Note: System Restore Points will only remove Apps and Programs installed after the selected Restore Point date. It will not remove word/text files or pictures etc.

Step 2. Disable Automatic Hardware drivers update
- Right click the Windows Icon, select the "Search" Function.
- Type "Control Panel" and select "Small icons" or "Large Icons" in the "View By" top right.
- Click the "System Icon"    
- Navigate to "Advanced System Settings" -> "Hardware"
- Click "Device Installation Settings" and Select "No"
**This will prevent Windows from interfering with your hardware drivers in future updates, but keep crucial security updates rolling.

Step 3. Windows Reset/Recovery
**This is a complete factory reset of the computer
**Loss of data can occur, so we advise you to backup your data if possible.

- Stay disconnected from the Internet after entering the OS again, then perform step 2. before allowing any Windows updates to take place.

Hope this helps

Regards

Voithos