My boxer pup is 8 months old and is having a jolly time destroying his beds in his crate

He is not bored, has plenty of mental and age appropriate stimulation, not left for long periods and has a variety of chew things in there with him.
I genuinely think he does it because he enjoys it which is fair enough but what can I give him to lay on? He’s got through a piece of vet bed too as I thought that would work but nope. He doesn’t eat the shreddings just has fun making them. The next step is a duvet as I know lots of dogs that will not touch them. I know the filling is bad but he never eats any of it so I’m prepared to let him have one as a trial.
If he shreds the duvet am I a meanie leaving him with just a couple of towels to lay on or will he be okay and it’s a case of try a bed again when he’s a bit older? He looks so happy when he’s doing it

but even though I’ve been buying cheap beds they work out as expensive toys! He doesn’t try to kill any of his toys, just his bed.
He doesn’t do it when we are there so we can’t stop him; I think he was told off once and now I feel he does it in secret

I’ve recorded him and there are no separation anxiety signs just a dog having fun at my expense. He does chew his other toys and freely goes in and out his crate but is shut in when we are out and at night.
So my plan was duvet, if that fails then towels or even nothing

but your wisdom is appreciated.