Create an option to duplicate calendar events
This has long been a feature of 3rd party apps like Fantastical and I don't understand why Outlook doesn't have it yet. It's such a no-brainer and so handy. Right-click an event | Duplicate.
I believe I used to be able to hold option down, drag an event and it would create a duplicate. When I do it now, it changes the mouse icon to include the "+" symbol, but it only moves the event - it doesn't duplicate it.