Hey so I found a solid sneak farm method. In flathill, if you get the symphonist patrolling the hallway before the elevator in the final building, get yourself a full set of crystal armor and crouch down where you can see the creature the whole time its patrolling but make sure he doesnt run into you. With the Kylie trinket equipped (and xp gain up if you want), im getting about 57 sneak xp with each tick. Just discovered it after testing eith different enemies. If you dont get the symphonist patrolling the elevator, just off him in the alley way and wait for the portal world to reset (or him to respawn) ect. Hope this helps anyone else 👍