You could also consult with TBest and Min and whoever else to copy their troll-handling methods. I don't think WZ Public Chat could handle a troll problem the size of what your server has but their techniques could provide a solid foundation for building on top of.
That behavior would get auto-banned by either the bot or any of the 16 moderators. The ban-list in our server is not small (notably the player known as karl, kept coming back with new discord accounts) and a few other rule-breaking things. We also have explicit media content filter turned on. I will say, that it's not like the WZ public chat never had problems. After all that is why we added the verification gate. I do say, it's in a safe place now, but the beginning had some hiccups. :)
With that being said, the server we have is open to everyone, which naturally includes the diplomacy community. If at any point, activity mandates separate diplomacy channels we will (re)add it, for example if any other server wants to move here. So far thru, WZ public never really saw use from the diplo folks. Which, is perfectly understandable as it might be easier for them to organize in a separate server.