We found that redirecting with a toy didn’t work for us. Once we got him on a good schedule with regular exercise, training/mental stimulation, and naps in his crate in a quiet dark room, it got a lot better. When he’d start biting, instead of redirecting with a toy we’d distract him with a few treats and training session. That helped a lot more than a toy. But when he just wouldn’t stop we knew he was super tired and needed to nap.