Banning IP’s can be difficult when people are behind proxys/vpns and you can end up banning the IP of an access point/repeater, like what happened in Grand Fantasia/Eden Eternal (I forget which it was, I was playing both at the time) and they accidentally banned the node for the whole of china.
All you can really do about the advertising bots is to make them jump through as many hoops as possible.
eg: You must finish the first main quest in the starting area before you can go to the city. This should force them to physically play the first area without automation as some of the quests require interacting with items that spawn in random spots and cant be targeted to determine their position. Some bot automations can still complete quests but only ones with fixed locations and target-able objectives. This would only affect them slightly as they still have an unlimited resource (time) to get around what ever is placed in their way but it’s 1 more hoop than the current zero.