Yeah, the activity numbers can be pretty wrong. There is an older issue about this on codeberg: https://codeberg.org/rimu/pyfedi/issues/424

I haven’t really dug into this issue yet, so I am not sure if the issue is that certain activities aren’t marking users as active recently or that the db queries are somehow not counting users correctly. I suspect it is the former, that certain user actions (eg vote, comment, etc.) aren’t then also marking that user as having been recently active.