How many calendars can I sync?
You can sync as many Google Calendars as you want between Notion and Google Calendar in either one-way or two-way sync. The calendars can be from different Google accounts within the same automation.
However, only one calendar will be the default for syncing new events. When you create a new event in Notion that gets synced to Google Calendar, it will go to the default calendar you selected. The rest of the calendars will still sync their events to Notion normally.
You can choose which calendar you want to be the default one when creating or editing the automation inside the Calendar Connections tab.