Thanks for voting!
One alternative is to subscribe to iCloud calendar with your Exchange/O365 email accounts or any Outlook account, and then sync the same accounts in Outlook for Mac. See details:
An error occurred while saving the commentWolfgang Meincke commented
I just purchased Microsoft 365 and was very surprised that Outlook does not automatically have all calendars and contacts from macOS/iOS available like you know it from many other third-party apps. I like the Microsoft Office package but for other reasons, I have to use macOS, so please tear down that wall and fully integrate with macOS/iOS, please!