Turn off Sleep/Wake Alarm
I found a way to turn of the Sleep/Wake Alarm:
1 Go to the Health app on your iPhone.
2 Tap Browse at the bottom right, then tap Sleep.
3 Scroll down to Your Schedule, then tap Full Schedule & Options.
4 Tap Edit for the schedule you want to remove.
5 Tap Delete Schedule (at the bottom of the screen).
iPhone 16 Pro Max, iOS 18