Finnish national holidays not appearing in Calendar app

Hi, I’m having trouble getting Finnish national holidays to appear in the Calendar app. I’m using an iPhone 13 and an iPad Mini 7, and both devices have the region set to Finland, but the system language is English.

Even with the region correctly set, the holiday calendar doesn’t show up in the Calendars list on either device. I’ve refreshed the calendar, restarted the devices, and checked all the settings I could think of, but nothing seems to bring the Finnish holidays back.

Does anyone know what might be causing this or how to fix it?