There are only two controls over Spotlight and calendars in Monterey and Ventura. In System Preferences > Security & Privacy, select the Privacy tab, then the Calendars item at the left. Check that you don’t have anything suspicious in the list, particularly if its checkbox is unchecked. Apps listed there should only be third–party products, and most should be checked unless you know they shouldn’t have access. Ventura’s equivalent is Privacy & Security in System Settings.
In Spotlight > Search Results, check that Events & Reminders is checked. Also check that, in the Privacy tab, you don’t have any folders or volumes that might contain your calendar(s). In Ventura, these are easier to use in System Settings > Siri & Spotlight.