Sometimes it takes a while for a bun to warm up to new vegetables
Thor is very suspicious of new additions to her salad. You can keep presenting them though and usually they will start to like the new veggie. You should try a variety of leafy vegetables like Sarah said. Carrot should be kept to a small piece (only about a thumbnail long) a few times a week at the most. It’s ok if he doesn’t like fruit, they are very high in starches and don’t provide any essential nutrients. They are fun as treats, but if he doesn’t like them I would just stop giving fruit altogether, no point!
Here are some vegetables that tend to be favorites with bunnies: Parsley, cilantro, basil, romaine lettuce, fennel, dill, spring greens, and spinach.
I’d recommend trying one new vegetable a week, don’t introduce too many things at once as it may shock his system. I’m sure you will find something else he likes 