Topic 5536692
Already the mass edited/deleted posts updater using the sitemaps has refreshed 100k threads (a pittance when you take note that there's over 5 million topics, but we're getting there!)
Last time I checked (2 months ago), I counted only 1,415,773 topics (102 MB txt file). Almost 75% is deleted.

Right. I forgot that I ran a query on my internal Elasticsearch node for the number of unique topics, and got similar to this number too.

This significantly cuts down on runtime! I still have to search for and remove any deleted topics post-2020 though (when I loaded your archive into the storage).