Help! Separation anxiety in German shepherd

Our 5 yo German Shepherd has always had separation anxiety but we’ve been able to combat it with “doggy proofing” and getting his energy out before we leave him home alone. We tried kenneling him for about 2 hrs one day to see if that helped but he broke out and injured himself so that’s no longer an option. The reason why I’m looking for advice is because we are currently staying at an airbnb for the next few weeks. Yesterday we tried leaving him home alone (after doing our usual “doggy proofing” like removing pillows and trash) well we came back after being out for about 2/3 hours and he had chewed on the rug and tore the couch up. I know it’s anxiety and not just naughty behavior or boredom because we have a nanny cam and video shows him frantically running around the house (looking for us I assume) and whining before destroying items. Advice?