the Samsung calendar is one of the few standard applications that can also display a birthday. birthdays can be added via a contact, but they can also be displayed in the calendar. what doesn't happen by default is a reminder or notification when the birthday is approaching. here we can set an "alarm" under the warning settings of the Samsung calendar. the reminder can be set up to 99 weeks before the birthday.

Android 10 (One UI 2.0)
Step 1:  Open the  Calendar -App
Step 2:  Open the  menu
Step 3:  Open the  Settings
Step 4:  Tap on  Alert settings
Step 5:  Tap on  Contacts birthdays
Step 6:  Choose desired  Option
  1. Open the Calendar-App
  2. Open the menu
  3. Open the Settings
  4. Tap on Alert settings
  5. Tap on Contacts birthdays
  6. Choose desired Option

Samsung Instructions