Using New Outlook on Windows for personal email, calendar, and contact management
So a useful function that had been working for years has been removed??? Why???
No, it hasn't been removed, it hasn't been implemented yet.
The New Outlook isn't based on the original code of Classic Outlook, it is a complete remake from the ground up. It's going to take quite a bit of time to get all the useful functions back in there but then with a modern code base.
If you rely on this feature, you can either use the workaround which I suggested or revert back to Classic Outlook; It will be supported for years to come.