The only way to bulk move is to delete category.
Problem 1 ) you cant move bulk topics from subcategory to category
Only Solution : Move category somewhere to become subcategory and delete subcategory .
Problem 2) you cant move bulk selected topics - Solution : None
Selection of multiple topics to moderate must be added in forum. No way for a big forum to move to wpforo if there in mot this function
I hope that you will add a fix for this in a futura update.