OnePlus
Show or Hide Holidays in the Calendar App auf OnePlus
OnePlus phones running Oxygenos pull national and regional holidays from a built-in calendar provider and display them automatically in every calendar view. This happens regardless of which calendar accounts you have synced, so the holiday layer sits on top of your personal appointments.
Add a work account, a personal Google account, and a shared family calendar, and the extra holiday entries push your actual appointments further down the day view. On smaller screens this makes it easy to miss a reminder buried between two public holidays.
To turn holidays off, open Calendar, then tap Open the menu, and use the Enable or disable Holidays option. Disabling it removes the holiday layer from every view without touching your synced accounts or existing events.
Turning holidays off is different from removing an unwanted calendar account. If your overview still looks crowded after disabling holidays, check whether a specific account or calendar is showing duplicate entries instead.
Re-enabling holidays later restores the same list right away, since the data is stored locally by the calendar provider and does not need a fresh sync.