Why not adding "Event" post type. Which would be dedicated for announcing and scheduling events. Things that users would be able to do are:
- Set a date and time for it
- Where it's happening (online or offline and add info about it)
- Generate buttons to add to calendars
That's petty much it. main thing really is picking a date and generating buttons. You kinda can do all that manually by typing up a post, but would be nice to have something dedicated to that.