Had a pup that liked to chew, replaced CT wiring 3 times. 3rd time I ran it through conduit, and that stopped him...for a while. Tried the chilli sauce + other secret erbs n spices, nothing worked.
He had a lot of other bad habits as well, so in the end, instead of trying to pass the headaches onto someone else, he got a final visit to the vet!
We've currently got a 6mth shepherd who likes to dig

Read about dropping their poo's in the hole, but had no faith in that working, figured he's just dig elsewhere...he just digs elswhere
He's certainly not bored either, toys in the yard, staffy to play with, walked 2 x a day, and I'm usually in the yard working. Now he's locked in his kennel of a night, and chained when no supervision for large lengths of time, hopeing after a while he'll forget about digging.
So only suggestion I could give is to chain him up when he'll be without supervision,. But have yet to see if that theory works