Birthday notifications missing on iPhone 15 Pro Max despite calendar settings

I have a confounding problem.

For over a year I have been trying (unsuccessfully) to get birthday notifications to appear on my iPhone 15 Pro Max.

On my desktop calendar (Version 15) I can see the birthdays. But even after every single checkmark on the left is checked, even after the notifications on my phone are set to notify for calendar, even after the scheduled notification for calendar is checked, there is nothing I get. And the widget on my iPhone for today's events which include a birthday, is blank and instead it says, "Mon Aug 18. No events today."

I have talked to Apple advisors, visited the Apple Store in the Beverly Center yesterday and worked with a service advisor there, and still, today, there are zero notifications on my iphone.

What am I doing wrong? How can such a simple request as a birthday reminder on my iPhone be so confusing and difficult to set up?

[Re-Titled by Moderator]

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