How do I prevent Mac apps from blocking the restart process?

My desktop is configured in such a way that a sudden power loss (or abrupt restart) would result in absolutely no data lost. I therefore want to make sure that updates can always install on schedule and that I don't have to manually close any programs when clicking the Restart button.

How do I force Mac to always restart without delay, completely ignoring whatever software might be running in the background?

In my experience the best way to keep apps from blocking an update install is to just close all GUI apps before going to bed - or putting my machine "to sleep".

I've also noticed that I need to logout of Terminal, especially.