I'll suggest an approach that works for me.

Ask yourself what it is you're actually doing / attending to / accomplishing, with regard to whatever notification you happen to see. Then identify similar ones; group them together; and work on that group at repeated intervals. It should feel like boring maintenance work — because the goal is to make work predictable in order to predictably achieve the outcomes you desire (and then to automate the work, if you want, to free up your time). This also helps to identify low-value types of activities and then deprioritize or eliminate them.

By way of your example, I want to take certain actions regarding special days involving people who are important to me (birthdays, holidays, anniversaries …). So periodically I attend to that because it's important. (Maybe that means I plan things out every week, or every month — up to you. And then the planned tasks — calling my buddy, shopping for gifts, writing and mailing cards — go on the calendar as planned work.) It's during that work period that I see triggers / upcoming items related to that group of items. Why would I want notifications or other interruptions about them any other time? Answer: only for things that are true emergencies. Maybe you should have a yearly repeating 15-minute calendar entry to call your friend on their birthday. (You are working from your calendar, right?)

The other tip I can offer is to do yesterday's incoming work today, and today's incoming work tomorrow. This lets you strategically plan how you will handle all of today's work instead of getting interrupted by it today and bouncing around trying to deal with it. Moreover, very few things need to be done immediately; many problems solve themselves with time; and sleeping on things can shift a large chunk of the time-consuming processing involved with it to your subconscious mind. (Furthermore, the habit of planning your work in advance and addressing it methodically is going to drastically reduce the number of true emergencies and even typical interruptions that you'll feel the need to deal with. It's a virtuous cycle.)

I'll leave you with the notions that practically everything is unimportant when you consider its place in the incalculable vastness of the universe; you never get your time back; and your health is of paramount importance.

P.S.: I somehow missed that you had the birthday on your calendar. This tells me that either you're not working from your calendar (big problem) or else you added the birthday as an all-day event instead of an appointment ("I will call my friend on their birthday every year at 12 PM and catch up for 15 minutes").