So these diet questions I'm asking about, have to do with how diet can affect a rabbits energy levels, and also boredom levels.
Sometimes a rabbit that's getting too much concentrated food or high calorie foods(eg. grains, sugars), can fill up on these, then they don't have anything better to do with their time, so find ways to exhibit normal rabbit behaviors such as chewing and being destructive. The solution to this is lowering the amount of pellets and high calorie foods, so that the bun spends more of its free time eating hay. They have less time to get bored, so less time to be destructive.
But therre can also be kind of the opposite effect of a concentrated high calorie diet. Some buns on a low pellet/low calorie diet, can get kind of anxious about feeling hungry, and so will obsessively look for food or find other ways of acting out. like being desctructive. So adding more pellets to the diet, when the rabbit doesn't have digestive issues or obesity problems that excess pellets might aggravate, can help fill them up faster and help them relax more.
It's diifferent with every bun, so it's finding if your bun is affected by diet and in what way he might be. It might be worthwhile to experiment a little with your rabbits diet, to see if it changes his destructive behavior at all. You can try feeding his pellets in the evening instead of the morning to see if filling up on pellets in the evening helps him settle down better. You can try increased pellet amounts to see if he's being destructive because he's feeling hungry. Though increasing pellet amounts will depend on if your rabbit has digestive or weight issues that would limit pellet amounts he gets each day. You can try decreasing pellet amounts so he spends even more time eating hay and has less time to be bored and destructive. Diet may not alter his behavior at all, or it could impact it significantly. I've had some rabbits that it made a big difference with their activity levels and what they spent their time doing.
You can also try different distraction activities. If your bun doesn't have a carboard/paper eating issue, you can try things like a new cardboard box to explore and destroy. Old phone books can also be fun for them to shred up. If you have access to rabbit safe tree branches/bushes, branches can also be a good distracting activity for buns.
https://wabbitwiki.com/wiki/Toys_and_games