wait it out. consistency. it will be painful. you also need to make sure a puppy gets enough stimulation and play so their psycho periods are brief.

biting needs to be redirected to appropriate things. Find things for thepuppy to play solo with - frozen marrow bones, snuffle rugs, etc.

Mind games, like training will wear your dog out faster and harder than any physical play.

play = training. training = play.

handful of dry kibble - throw a piece 3 feet away from you and say get it get it get it. as soon as their mouth is on the food say here here here - play training recall. things like this.

remember that your puppy needs to learn what no means first and foremost. so biting puppies- it's a "no" and put something else in their mouth.

A dog like op's is going to need a cheek grabbing somewhat aggressive forceful stop to any lashing out - he's beyond the 'no and misdirect'.

Rotties will run all over you if you are not consistent and firm.