we have used constant supervision and bitter apple with our pup and have so far had no problems with chewing items in the house. he is never left alone unsupervised in the house during the day time, for more than a couple of minutes at the most. if i go outside, have a shower, or for whatever reason i can't watch him, he goes in his crate or he comes outside with me. i'm hoping this approach will get him through the chewing phases and prevent him from developing the habit. he does chew on his own toys and loves his venison ears, but if he grabs anything else i've always been in the same room to catch him and discipline him. it is a pain in the neck being on constant watch duty and having pet gates up in the house, but he is still too young to be trusted. its not so much that i care whether he ruins a cushion or two but i just don't want him developing the habit of thinking he can chew on anything and everything.
during the work day he is outside and i basically think ahead and make sure he can't access anything i wouldn't want destroyed. i gave him our old lounge chair to play with outside, which he's ripped apart, but he hasn't transferred that behaviour inside...although as i said, i never leave him alone long enough to do that, and he's always been a heavy sleeper at night so i haven't had to worry at night time.
bitter apple spray really worked for us, i'm not sure if you mentioned trying it? its not cheap, but our boy hates it and will run away from whatever i spray it on. from 8 months old he has been sleeping unsupervised at night in the family room and we haven't had any problems so far. he could quite easily tear up the whole house if he wanted to...he's already 45kg lol. every now and then i'll still do a cursory spray around the edges of the furniture just to keep him on his toes :D good luck and i hope you have some success in stopping the behaviour.
but...if we wanna talk about digging...oh my lord.