Have you tried baskets? You can get some quite cheap untreated wicker and seagrass type woven baskets from DIY shops and cheapo pound shops. My lot love destroying them. Mostly they pull bits off and leave them, but they do munch some so you need to check what they're made of and make sure they haven't been treated with anything dodgy.
Homebase were doing three nested baskets with wooden handles for a fiver a couple months a go. They might still have them. They last ages even with four angry little rabbits attacking from all sides.
Another thing worth a try are roll-a-nests. They sell them as woven nests for hamsters. They made out of hay on a metal frame. They enjoyed destroying those.
I had one of those bunny castles too. They gutted the poor thing. Eventually I had to condemn it as it became structurally unsound.
They like the fiddle sticks too. The ones you can bend to make tunnels and things. But they mostly seem to like them lying flat so they can stand on them and rip the bark off.
What else worked...the plaits of straw were just instantly destroyed and ignored. Twig balls lasted a little longer, but after a couple of days they were mostly dead and ignored. The weeble type feeder for ferrets was popular, but it made a lot of mess and started some fights, so I don't use that anymore. Everything else just gets ignored. Dangly toys, balls with bells, cholla, that sisal carrot thing, toothing rings, all ignored.
Baskets, cardboard, wooden tunnels, those vegetable parchment tunnels and the roll-a-nests, are the only really popular toys with my lot.