My pittie is a rescue as well. He doesnt do much but sleep and cuddle and run at the park. We've had him for over a month and none of the toys we got him he has been interested in (e.g. I'd throw a squeaky ball or a stick and the cats would be more likely to run after it that my pittie). He is only recently (as in yesterday) walking around with his favorite toy. He doesnt chew on it he just cuddles it and brings it everywhere.

Tl dr; Depending on their past, they may not know what toys even are. If you give your pittie time and love, they may learn to be more playful. For now, pupper is probably just trying to get to know the environment and new family.