No audible sound for calendar alerts

I read a previous post from someone else with the same problem. His fix was to flip the side button to sound “on.”

I have done all settings resetting he did. To which nod of thoroughness was given. I have turned the phone off and on.

My side button is set to sound on.

I have changed the calendar alert ringtone to a long and loud tone.

I get text alerts. My phone rings.

I can be holding the phone and looking at it. ( running multiple tests trying to find a solution) a banner briefly silently appears and vanishes.

I don’t know if it is suppose to linger or be visible when I bring up the Home Screen after it has been dark.

Is a calendar alert suppose to be visible in Notifications, until acknowledged?

I thought I used to have to acknowledge looking at the appointment for the banner to vanish completely.

My solution has been to set an “alarm” for each calendar event.

My calendar events used to alert perfectly every time, until they didn’t.

I don’t know when the lack of audible alerts started. Possibly when I got my new iPhone 13 a couple months ago. Possibly a longer or shorter time frame than that.

I look forward to hearing from you.