Trouble with IPhone alarm

Check the following

1. Do you have any third-party Alarm App installed which is interfering with the default Alarm app?
2. Do you want to say there was no Vibration even?
   1. Settings > General > Accessibility > Vibration > Vibration [Enabled] or [Disabled]
   2. Settings > Sound > Vibration [Enabled] or [Disabled]
3. Was there any Alarm symbol on the status bar on top (Watch the GIF below). Though this shows up on your device (As per your post)
4. Turn on Set Automatically in Settings > General > Date & Time. This automatically sets your date and time based on your time zone. If there’s an available time zone update, your device lets you know.
5. Allow your device to use its current location to determine the correct time zone. To do this, go to Settings > Privacy > Location Services > System Services and select Setting Time Zone.
6. Check that your device shows the correct time zone in Settings > General > Date & Time > Time Zone.
7. Probably you have set the Alarm Sound to NONE

Watch the GIF below

How to edit an alarm

1. Open the Clock app and tap the Alarm tab.
2. Tap Edit in the upper-left corner.
3. Tap the alarm, make your changes, then tap Save.

How to set and change alarms on your iPhone - Apple Support

Probably you have set the Alarm Sound to NONE

Watch the GIF below