By default, the Samsung calendar does not show holidays. This means that neither the Calendar app nor the widget will show individual holidays.
If you want to change this, you can use this tip to quickly display the holidays within the Samsung calendar:
It is important that you have a linked Google Account, as the holiday dates are taken from this source.
Show ALL holidays in Samsung calendar
1. Open the Samsung calendar app
2. Go to the three-bar symbol in the upper left corner.
3. Please select your Google Mail address.
4. Place a check mark in the box for "Holidays in Germany (or your home country)".
The Samsung Calendar will then show you all German holidays.
You now know the procedure to display all holidays within the Google Calendar.