Unable to Turn off sleep tracking/score

To stop the tracking, get rid of the sleep score, and clear your watch screen, follow these steps:

1. Turn Off Sleep Tracking on Your Apple Watch

You can disable the sensors completely so the watch stops monitoring your sleep: 

1. Press the Digital Crown on your Apple Watch to open your app grid/list.
2. Open the gear-shaped Settings app.
3. Scroll down and tap on Sleep.
4. Toggle off the switch for Sleep Tracking.
5. (Optional) Scroll down and turn off Sleep Screen if you don't want the watch face changing or dimming automatically at night. 

To stop your iPhone from prompting you about sleep goals or generating score indexes:

1. Open the built-in Health app on your iPhone.
2. Tap the Browse tab at the bottom right, then select Sleep.
3. Scroll down to the bottom and tap Full Schedule & Options.
4. At the very top, toggle off the main Sleep Schedule switch.