Ghost alarm goes off daily at 7AM without alarm set or Sleep enabled

Unscheduled alarm goes off at 7AM local time without any previous set up; checked calendar events, reminders, alarms, and Sleep focus (disabled), but no luck; I can reproduce the event by manually changing the phone clock in the iPhone; finally, checked every tone and sound on my phone, and it is not available, and I haven't purchased or created any ringtones.