Did your iPhone alarm ring today?
I have two different models and both did not ring the alarm. Both have alarms set to ring at specific time every weekday. I recall this might have happened in the past also.
Did it ever happen to you?
Mine did not! I distinctly remember setting it last night but it only shows tomorrow's morning alarm. I set my alarm through the "sleep" feature where it gives you a schedule and automatically sets an alarm that you can modify day-to-day.
Possibly related: I note that my macOS calendar has simply been failing to notify many of the alerts that I have set, and I have been late for meetings, etc, as a result. I can watch some events pass with the calendar open and no alert arrives. Sometimes I do get alerts. This has been going on maybe a few weeks?