How do I delete an alarm not from the Clock app on my iPhone 8?

So far, you are asking us to guess on what third-party app you might have installed on your phone. To narrow things down, can you tell us what third-party apps you have installed?

1. Do you have any third party Alarm App installed which is interfering with the default Alarm app?
2. Do you have BedTime alarm set?
3. Was there any Alarm symbol on status bar on top (Watch the 1st GIF below)
4. Check your Reminders Today Notifications (Watch the 2nd GIF Below)