Hi
I'm not sure I'm knowledgeable to give much advice in your case, but just wanted to stop by to salute the rescue of a dog, specially an abused one
My little grain of salt though :
- destruction is not something that would go overnight, so environment control is much needed. With ours, when we couldn't watch him, he would be in a playpen, or to avoid destruction on stuff we really didn't want to, we would put that stuff in the kennel, not the dog :) One of our sofa was in a kennel during first chewing phase :)
- redirection with high value treats : the importance of the treat value can be underestimated and is more significant that we may think. Some stuff we were struggling with, was settled quite fast once we change the treats
- finding the adequate replacement : giving him an alternative thing to chew on and destruct would save the stuff you value... but it's not that easy to find : for example, the Kong, which is often "the Grail of toy to keep your dog busy" was a total failure with our pup... Chewing stuff like hooves, or horns, was the way to go for him
It's personal experience that worked with our pup, cannot guarantee it would be efficient with your dog
Still, hope it will help
++