I’m not sure I can quite envisage what you have in mind for including categories, tags, and topics, with a post count for each, in the same report/query.
I think you could likely do it in two - one for categories and one for tags, with a count of new topics and new posts within a certain timeframe for each one. Maybe even include the number of users posting?
So it would give something like this as the result table:
| category | new topics | new posts | users |
|---|---|---|---|
| category a | 9 | 15 | 4 |
| category b | 56 | 167 | 32 |