Some rabbits, though a minority, may not like a lot of toys. Your rabbit sounds pretty much like my netherland dwarf — he doesn’t chew toys or play with anything. He just lounges all day (he doesn’t even flop, haha). If he’s not showing frustration behaviors, such as destructive tendencies, and he’s eating and drinking and pooping fine, he may just be more chill. He’s also on the older side, so perhaps age, though the relationship between the two is pretty weak from what I’ve read with other members’ stories!
Since he does engage with you, something you can do is try to engage with him more often. I know I suspect a lot of my ND’s behaviors come from him observing that… I very frequently… just sit.. and… do nothing, haha. Perhaps trying to teach him tricks, cues, etc may be fun and engaging!
The answers provided in this discussion are for general guideline purposes only. The information is not intended to diagnose or treat your pet. Seek the advice of your veterinarian or a qualified behaviorist.