'Do Not Disturb' will not turn off

You don't turn off Focus through Settings. You turn it off in the Control Center.

Pull down the Control Center. Tap on the icon next to the words "Do Not Disturb" on the Focus button. Do not tap on the words. Once you tap on the icon, the word should change to "Focus". It is now off.

Glad it helped!

Yes, Focus/Do Not Disturb, while powerful and useful is perhaps not as easy to use as it could be.

How are you trying to turn it off? Are you going to the Control Center and tapping on the icon on the Focus button? What happens when you try to turn it off?