How to Set up Your Google Calendars in Apple Calendar
To add your Google Calendar events to Apple Calendar and have them synchronize automatically:
Add Individual Google Calendars to iOS
You don’t need to sync all the associated calendars in your Google account to iOS.
How to Use Google Calendar with Your iPhone or iPad
Several Google Calendar features don’t work on Apple Calendar. These include the Room Scheduler and emailed event notifications. Also, you can’t create new Google calendars using Apple Calendar. Go to Settings > Passwords & Accounts to turn on or off sync settings, including your calendar. Tap your Gmail account to reveal the switches for mail, contacts, calendars, and notes. By adding your Google account to iOS, you’ve configured it for the Apple Mail, Calendar, Contacts, and Notes apps. However, apps from the App Store, such as Microsoft Outlook, cannot read from the iOS Settings configuration; set up your Google account individually in non-Apple apps.