it isn't just "lack of exercise" or boredom that leads to destroying objects -
Dogs do it 'cuz, A
, they can, & B
, no-one's taught them any different.
Well-exercised & happily busy dogs will still rip stuff - chewing is a lifelong dog-behavior, but gnawing on something isn't the same activity as shredding an object, & provides a different kind of satisfaction.
Giving a dog legitimate objects to shred outdoors, such as empty cardboard boxes, can satisfy their yen to rip the H*** outta stuff, without destroying anything of value.
Most untaught dogs will use anything in the environs as a chew-toy or a destroyable hunk of busywork - if it's not too big to fit in their mouths, isn't made of concrete, stone, metal, or brick, they'll chew it. If it's shreddable, thy'll shred it.
Dogs didn't evolve with sofas - anything chewable, gets chewed; if they prefer a certain texture, they may choose fabric, foam, paper [ripping ppr-towels, TP, facial tissues, etc, is actually a heritable behavior that can be compulsive - known breeds that may carry this trait include Labs & GSDs], wood [chair legs, cupboard doors...], etc.
teaching a dog NOT to shred toys is time-consuming, but simple:
offer a toy, & as soon as the dog puts A PAW ON IT, take it away instantly.
They can't rip it without pinning it down; they can only mouth it. Putting a paw on it means they are about to rip into it, so remove it. // Wait 5-secs or so, re-offer it. See the paw put on the toy?... take it away. // Repeat, ad infinitum
It took me about a week of daily bouts of offering my then-15-WO Akita soft toys & plastic toys multiple times a day, to get her to the point that she didn't try to shred or puncture them within 45-seconds flat. So yeah, the process is a PITA - but sheer bloody-minded repetition, AND management
so that no wreckable items are within dog-reach when they are not under Ur direct supervision, will eventually bring the lesson home: if they want to play with the toy, PAWS don't go on it.
That doesn't mean U can leave soft-toys with the dog when U are out of the room, or not at home - that's too much to expect. Dogs who love to rip can't be left with tempting items & then blamed for shredding them - set the dog up for success, save the $$ U'd spend to replace them, & PUT THE TOYS AWAY when U aren't supervising.
JMO & IME,