I cannot figure out how to turn off do not disturb. It turn on automatically on all my devices.

If you are sharing your Apple ID with others then please check if someone else is enabling it.

Settings > Focus > Share Across Devices [Disable]

Turn on or schedule a Focus on iPhone

• Open Control Center, tap Focus, then tap the Focus you want to turn on (for example, Do Not Disturb). ... 
• To choose an ending point for the Focus, tap , select an option (such as “For 1 hour” or “Until I leave this location”), then tap.

Turn on or schedule a Focus on iPhone - Apple Support (IN)

Yes, very much the On/Off featire still exists with variety of other options. Simply Tap to On and Off.

Please pull down the control Center and watch the fun. See the pic below which is self-explanatory.

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