Since Outlook doesn’t support the import of CalDEV files on Mac, only the web-based solution can be implemented on Mac. If you want, you can take the assistance of iCloud’s app or visit its website to export an iCloud calendar to Outlook. Part 1: How to Sync an iCloud Calendar with Outlook: via iCloud App and Website
Part 2: How to Fix the iCloud Calendar not Syncing with Outlook Issue?