Schedule an unstoppable Windows 10 shutdown event

Yes, you can do this by creating a scheduled task and use shutdown -s -t 0 and set the trigger to the desired moment of shutdown.

This will not give a warning about a shutdown either. Of course, anyone who looks into Scheduled Tasks will find it and can disable or delete the task which prevents the shutdown, but no one is going to unless there is reason to look for it.

Also, after the shutdown, the task will remain there even though it will not activate again, which allows you to quickly edit it for a rearm, but if you don't want to leave evidence, then that won't work for you.

If you want something really stealthy that cannot be aborted, you will need a service with a monitoring agent. You install software on the computer that periodically checks with a central server. From the central server, you schedule the shutdown by sending the shutdown command.

Those are your options.

Do note, if your idea is to ensure that the computer cannot be used after a certain time (say, to lock out a child) this is not the way to go. Instead, setup an account lockout policy with active hours. That way, the account in question will get a notification before the timer that they will be logged out, and that cannot be stopped. Once locked out, it cannot be logged in until the timer allows this.