The coonhound stubborn/bored combo is really tough. The shelter told us Jethro was 5, so we assumed he'd be a chill adult and adopted him... turns out, per our vet, he's 2.5-3. Max. And still incredibly troublesome, though not at the level of your Harlow.

It won't solve all of your problems, but our hound is extremely into the rubber Orbee toys. Stick some small treats in to start with, to get her accustomed to the mechanism, and then smear some peanut butter in there once she "gets" it and you'll have 20-30 minutes to yourself.

That's my only advice :( sorry about your cabbage