If you’ll completely ignore him when he’s barking, he will stop. Not right away., mind you. It may take several days. If he’s destructive, confine him either in a crate in the room with you, or attach a leash to you, so that you are there to correct bad behavior, but otherwise simply ignore him. I know it’s very hard to do.

It seems as though he’s trained you well; he barks or otherwise interrupts you and you stop what you’re doing and pay attention to him. Doesn’t matter that it’s negative or positive, to him you stopped what you were doing and focused on him.

Give him the correct things to chew. Maybe fill a kong with kibble, broth and some chopped veggies, seal it with peanut butter and freeze it. Give it to him in his crate, or on a hard surface, because it can be a bit messy.