That’s not doable today, groups and categories can only be created by staff. After they are created, both categories and groups can be self organized via category moderators and group owners.
That said we are currently working on a plugin to allow this very use case.
Not sure what exact metric you are looking to compare with but we have instances doing over 50M page views and over 500000 posts a month.
What is the type of events integration you are looking for?