We have time_read (along with many others like days_visited, posts_read_count, topics_entered, etc) in the user_stats table. But this is overall, not by visit.
There is the topic_users table that has last_visited_at and total_msecs_viewed
I don’t see how progress through an individual topic could be graphed over time because AFAIK total_msecs_viewed Is cumulative.
But I think the table could be used to get an imperfect hint at reading activity across topics over time.