On Windows 10 1809 or earlier versions, due to Windows limitations, the device will reboot even without a System Update prompt.
On Windows 10 20H2 or later versions, the prompt will not be displayed, and the device will not reboot. The reboot prompt will be suppressed and if the prompt is displayed, the reboot will not be honoured. You must reboot the device manually.
The system update reboot prompt is not applicable for devices that are connected through the RDP session for non-console users and terminal server environments, even if the update prompt is configured.