You leave for an eight-hour day and come back to a chewed remote, a torn cushion corner, or a dog who's spent the whole day pacing by the door. He wasn't bored on purpose — he just had nothing else to do.
So you try a longer walk before work, which helps for about an hour. You leave out a basket of toys, and by day three he's walked past every one of them, because nothing in that basket moves, reacts, or surprises him the way something alive would.
Daycare and a dog walker both work, if you can fit another $25–45 a day into a normal week. A treat puzzle buys you the ten minutes it takes him to lick it clean. None of it covers the six hours in between — the hours when a bored, under-stimulated dog is the one making decisions about your furniture.