Usually, there are a few reasons why you don't see your events:

• After enabling the connection between Craft and your Calendar app (more info here), in some cases you need to fully restart the app on Mac
  • Please stop the app via Activity Monitor (that guarantees that the app will fully stop), and then restart the app.
• If the issue persists, it is likely to be related to your macOS Calendar settings, as Craft syncs with that only. So in this case it is worth checking the Calendar -> Accounts settings panel as you might need to complete the authentication process for your Google account again.
• Another solution could be setting the Calendar refresh rate to every minute under Calendar -> Preferences -> Accounts -> Select the affected account -> Set Refresh