[Google Calendar] Can I use DAVx⁵ with Google Calendar?

Google Calendar does not show calendars by DAVx⁵

DAVx⁵ will sync data to the Android Calendar storage from where all other apps can read/write data to it. 

Google Calendar does by default not show DAVx5 synced calendars. To enable it open the side drawer and go to SettingsManage Accounts. In the list of Non-Google-Accounts activate the DAVx5 account(s). After that you'll be able to select various calendars from the side menu so that they are displayed in the calendar app.