Hello zauxna,
According to the steps found in the article you came from, Use Bedtime to track your sleep on your iPhone - Apple Support, here is how to turn Bedtime off:
1. Open the Clock app and tap the Bedtime tab.
2. Under Schedule, tap Bedtime or Wake Up.
3. In the top-right corner, turn Bedtime Schedule on or off.
This turns off both the bedtime reminder and the wake up alarm.
If you are not seeing this option, power cycle the iPhone using these instructions: Restart your iPhone - Apple Support While simple, this can refresh the iOS, apps and connections.
If it still not appear, reach out to Apple Support here: Get Support
Have a good day.