Is there a way to prevent moderators from purging topics / posts and change it to soft-delete topics and posts instead? It'd be a nice precaution incase a moderator account is compromised or a moderator goes rouge.
At this time I don't believe so, you'll need to create some sort of script to automatically execute the privilege removal call and run it on all of the categories.
And thank you so much for pointing me to the right direction. I was not clear how to delete/update these database settings. I have used Mongo_Express for this and cleaned the database according to your referenced topic. And it finally cleared the unwanted topics from my forum.