In order not to confuse the stored reminders for appointments and events in the Calendar app on the OnePlus smartphone, we can assign an individual color to each appointment category of the different Google Accounts.

Note: This includes, for example, birthday reminders.

Android 10 | OxygenOS 10.0
Calendar colours -  Open the  Calendar app
Calendar colours -  Open the  menu
Calendar colours -  Open the  Settings
Calendar colours -  Choose a  category
Calendar colours -  Tap on  Color
Calendar colours -  Choose a  color
  1. Open the Calendar app
  2. Open the menu
  3. Open the Settings
  4. Choose a category
  5. Tap on Color
  6. Choose a color

OnePlus Instructions