See https://commons.wikimedia.org/wiki/Commons:Monuments_database/Categorization/Statistics
Both the counts in the table and the edit summaries in the history
Updating categorization statistics. Total: 6980 Categorized: 0 Leftover: 6980
While I know for sure that some of these runs have categorised at least some pictures, and that the process concluded in one go.
But there are solid looking unit tests for these methods 🤔