The game is just very CPU demanding. I recently replaced my computer that was running a 8700k CPU with a 1080TI GPU. New rig has a 14700F CPU and RTX5070 GPU. I went from having 30 fps in heavy areas (infront of bank in Dornogol) to still just 60-70 fps in those heavy areas now, though I get 200+ in the open world.
Quazii put a very nice and detailed video together a few months ago for optimizing fps in WoW regardless of what computer/cpu being used. A few people in my guild recommended it to me as it improved their fps so I gave it a try and it did improve fps slightly on both the old and new rig. Worth looking into, if you google the name mentioned above and fps in the same search it should come up. Spending 15-30 mins can net you some nicr fps and visual improvements within the game.
Side note, in your ingame WoW Graphic Settings, if you have vertical sync enabled with a 70fps set monitor or your main Foreground FPS box is set to 70 it will 100% be throttling your FPS in game.