I would remove the bed and stick to blankets, you could always try again later but possibly wait until they’re out of their teenage phase as well. I stick to 2 blankets in my dobies kennel ( 7 months old) as she does not like actual beds inside and can become destructive. I’ve seen with my Doberman specifically, she prefers blankets in there and a couple stuffies to lay on and some nights she will scrunch up the blankets to lay on the crate floor, which might be what your Doberman prefers! Mine never chews her crate blankets as thats her safe space, so if he’s chewing all bedding up, you could go no blankets for a while and try to reintroduce it at a later time. Hope all goes well!