Just query them all in parallel and populate the map, as the results come in, with a 30-second timeout.
Discussion
And have most kinds deselected, by default. Limit it to kind 1, with a "see all results" toggle.
Most people who post infrequently, use kind 1.
According to nostr.band’s stats, there were 20,670,324 kind 1 events in the past 24 hours.
But what are the chances that they all came from someone's followers?
