How do I remove certain holidays from my calendar (but not all us holidays)?

I want to use the app already on my phone; I don’t want to buy a new app and have to re-enter a years’ worth of work schedules (my workdays vary and are not onna fixed schedule) onto a new app.

Why is Apple so inflexible on this? It comes across as social engineering—forcing us to “recognize” events that are irrelevant or unnecessary on our calendars.