Maybe go even lower value. Esther will do anything for food so I know well your struggle! Maybe a carrot? She'll eat carrots, but given something else she'll latch on to the else. An apple slice? Broccoli? Blueberry, banana, cantaloupe, celery, green bean, spinach, or some other dog-safe less exciting snack. If one of those works then you can slowly work your way through the list from least desirable to most.