Honestly, she sounds fairly typical for a six month old puppy...they just don't "settle" much! You're doing a lot of great things that will help her develop into a sensible adult dog, but might not produce overnight results. Glad to hear you have an x-pen and are using it, as management helps a lot at this stage.
I do what kmes suggested, biofeedback exercises to teach my dog "this is what being relaxed feels like," do Dr. Overall's relaxation protocol, and also capture calmness whenever I have the opportunity. But a lot of it simply depends on your dog growing and maturing, which she will surely do in time. You might also try some chew toys like antlers and cow horns, which are sometimes more appetizing than other toys (and are somewhat similar in texture to wooden chair legs), and then rotate those so that they maintain higher value.