It takes another hour, can I close the laptop without him stopping the process?
That depends on how your laptop is set in the Windows energy saving options.
Usually it switches to standby with the lid on when it is on battery power. This is usually deactivated on the fixed current and it remains on. That is the typical attitude.
Then I'd rather leave it open. Make the screen dark, set it with a darker background… Then I save at least a little electricity
That depends on your settings. Just enter (Windows 10, I assume?) "Close" in the Windows search bar, then you get the option "Change behavior when closing the laptop" and you can adjust the settings…
