We can select or add more alternate calendars on the Huawei smartphone, the following options are available:

Android 10 | EMUI 10.0
Step 1:  Open the  Calendar app
Step 2:  Open the  menu
Step 3:  Open the  Settings
Step 4:  Tap on  Alternate calendars
Step 5:  Set an  alternate calendar
  1. Open the Calendar app
  2. Open the menu
  3. Open the Settings
  4. Tap on Alternate calendars
  5. Set an alternate calendar

Huawei Instructions