If you were making a social app, how would you minimize trolls?
How would you minimize the # of trolls and spammer account signups? Just curious.
The best way I found is recaptcha on signup to stop around 90% of spam bots, and shadow ban trolls so they can still see their activity but no-one else can.
Use the robots9000 approach. No duplicate posts allowed. It works well for /r9k/ and for some various other sites I've visited.
Have you considered fail2ban?