Fair enough. You can do what I did to disable the task (it may be a different UpdateOrchestrator task - I just didn't want my laptop rebooting when it felt like it so I disabled the Reboot task), then:

Open an elevated Command Prompt

Run SCHTASKS /Change /TN "Microsoft\Windows\UpdateOrchestrator\Reboot" /DISABLE to disable the Reboot task (assuming it's the Reboot task you want to disable)

Grab NSudo (I won't link to the site I got that from because of this sub's rules, but its source is here: github.com/MouriNaruto/NSudo)

Run NSudo - set it to open cmd and have it use the TrustedInstaller user.

Run icacls "%WINDIR%\System32\Tasks\Microsoft\Windows\UpdateOrchestrator\Reboot" /inheritance:r /deny "Everyone:F" /deny "SYSTEM:F" /deny "Local Service:F" /deny "Administrators:F" inside the new CMD window. This will prevent the task from being enabled again. This assumes you're running an English version of Windows - translate the user names as necessary or find the SIDs, if required.

I've had two cumulative updates now and the task remains disabled.

Grrr