My bun (Butter) is confined to a spacious cage (54in by 60in) and has no space to really play. I live in a garage w/ 5 other people so its kinda crazy. I tend to get a little creative with all the amazon delivery boxes I get and have built some play things for butter to chew up.
Butter used to take out hay from a feeder box, stomp it down, then ate some and poo on it too. I’m not sure what the dimensions on your litter box are, but could it be possible that its not spacious enough? Once I got Butter an “IRIS Open Top Cat Litter Box”, he seemed to like it better than what I had used before, which was a 2×2 plastic bucket. Since it was a cage, I attached a “Kaytee Hay n Food Bin Feeder w/ Quick Locks” to the cage and hung it partially in the litter box. It was low enough where he could reach for the hay to eat, but high enough where he couldn’t not grab everything out at once. I also use shredded newspaper as an alternative to the hay being on the ground of the litter box. Since newspaper is compost-able, I tend to dump everything out in our backyard planter. Great fertilizer!
Since I also work long hours (10-14 hours), I generally stuff the Food bin with like two days worth of hay where some of it popping out. So far so good. Hope that helps a bit!