Thanks for getting back to us here in Communities, BorreBoy.
To confirm, is the only an issue with the new user account? Do you have another user and if so, does it unlock as expected?
Per this article, are all requirements met? Unlock your Mac with Apple Watch - Apple Support
•Your Mac has Wi-Fi and Bluetooth turned on.
•Your Mac and Apple Watch are signed in to iCloud with the same Apple ID, and your Apple ID is using two-factor authentication.
•Your Apple Watch is using a passcode.
Unlock your Mac
While wearing your watch, just wake up your Mac—no need to type in your password.
Tip: Make sure your Apple Watch is on your wrist and unlocked and you’re near your Mac
Are you trying to unlock the Mac after a fresh boot, restart or logged out of a user? If so, then not being able to unlock is expected. "The first time you log in after you turn on, restart, or log out of your Mac, you must log in by entering your password manually" Unlock your Mac with your Apple Watch - Apple Support
See if the same thing occurs in safe mode: How to use safe mode on your Mac - Apple Support
How to use safe mode
Determine whether you're using a Mac with Apple silicon, then follow the appropriate steps:
Apple silicon
1. Shut down your Mac.
2. Turn on your Mac and continue to press and hold the power button until you see the startup options window.
3. Select your startup disk, then press and hold the Shift key while clicking “Continue in Safe Mode.”
4. Log in to your Mac. You might be asked to log in again.
Intel processor
1. Turn on or restart your Mac, then immediately press and hold the Shift key as your Mac starts up.
2. Release the key when you see the login window, then log in to your Mac.
3. You might be asked to log in again. On either the first or second login window, you should see ”Safe Boot” in the upper-right corner of the window.
Keep us updated.
Cheers!