Unable to schedule restart at a specified time after Windows Update

I'm running Windows 10 Pro 21H1 on an unattended PC to manage a door entry control system. For operational reasons it's important that Windows Update should only initiate system restarts overnight after midnight.

Initially I configured Windows Update settings to only apply updates outside active hours which I'd defined as 07:00 to 01:00 which should have given a 6 hour window from 01:00 to 07:00 but for the last few days Windows Update indicates that the device needs to restart to install updates.

My next step was to use Group Policy Editor as follows:

Configure Automatic Updates = Enabled, option 4 autodownload and schedule the install every day at 0300 every week.

Always automatically restart at the scheduled time = Enabled with 15 minutes for users to save their work.

No auto-restart with logged on users for scheduled automatic updates = Disabled.

Windows Update still continues to show that a restart is required with the message "Your organization will restart your device at 03:00 to finish updating Windows. Or select Restart now to run more smoothly and securely right away"

What else should I do to force these restarts to happen automatically at 03:00?