The funny thing is, many people reading this thread or even commenting on it will have been manipulated by operant conditioning, and may even be playing the game only for that reason even if they think they're not. Blizzard is the master of operant conditioning, it's partly why their games are so popular. Look at Overwatch and its shiny loot boxes.
OP, if, like many others, you are particularly susceptible to Skinner Box mechanics and cannot moderate your play time in WoW then you may have to abandon the game and possible the genre entirely. I am the kind of person who can easily get sucked in to playing way too much and consequently I take regular breaks from the game.
Have you tried setting an alarm for, say, 2 hours time, and making yourself log out no matter what when the time is up? That might be one way to help. If you want to quit entirely then find another pursuit.