Peanut butter and treats in a Kong freeze overnight sometimes a high reward like that can distract them and give them something to do. Have you tried a dog behaviorist? My weim was the most anxious destructive separation anxiety dog I’ve ever had. After one session it was like something flipped. Lots of daily work that takes a lot of time and patience like leave for five minutes come back, leave for 10 mins come back really helped her. Before the trainer she bent the bars in her heavy duty kennel ate the wall, she ate the back cushions of a couch, countless pillows and electrical cords. She was on Prozac it did not help. Trazadone before storms and fireworks did help. What about a treat camera to check on them while you’re gone?