Digging and chewing are bunny behaviors, not really hormonal behaviors. Neutering might calm those urges down, but they will not stop. Youll have to find objects its acceptable for him to chew on and dig through. I suggest looking into a diggy box

Similar with the couch issue. Many rabbits, fixed or not, love to pee on soft things such as couches and beds. Many users use covers, or cage their couches/beds so the buns cant reach.

Neutering (or spaying, as the case may be) abates hormonal behaviors, but the essential rabbit behaviors will always be there. In fact, a lot of folks say that “fixing” a rabbit allows their real personality to shine forth, unimpeded by those pesky hormones! It sounds like Jett is getting along pretty well overall, especially with his litterbox habits. Of course, altered buns still do retain territorial instincts, though to a much milder degree than before the operation, so you should expect to see Jett continue to drop the odd “territorial” poop outside his habitat, or chin something, when he wants to mark a new place as his own. Before he was neutered, circling your feet and honking was a courtship demonstration, as odd as that may sound from bunny to human; now, it’s just a demonstration of affection. He’ll always want to dig and chew, so get him a digging box like Mikey says (I need to do that for my own two buns, though more as a means of engaging their play instincts than because they’re particularly aggressive about digging) and provide plenty of safe things for them to chew. Keeping the hay available at all times will help a lot with that, since not only do bunnies need it for their GI health but masticating the tough hay strands does a lot to help keep their teeth worn down and growth in check.