Can I make "Do Not Disturb" permanent?
I used the hacky workaround in this post on my slightly older Macs and it worked like a charm.

https://www.macobserver.com/tmo/article/os-x-10.8-turning-off-notification-center-permanently


  Turn OFF Notification Center Permanently
  
  Here's the best way to permanently kill the Notification Center. Open the terminal and type:

launchctl unload -w /System/Library/LaunchAgents/com.apple.notificationcenterui.plist 

  
  The Notification Center icon will disappear from the Menu bar at the top. There will be a visible gap, but the system will close it up the next time you click the mouse. Notification Center has been terminated.