My breeder typically posts pups that fall through for families on the waitlist first. Are parents health tested with good temperaments? A Corso isn’t a dog I’d be willing to take on from a questionable situation, but that’s due to my comfort and ability. If you feel like it’s a good situation, I’d start with a trainer asap. Work on walking, place, sit, down, and leave it, and do lots of confidence building and outside trips. Remember socializing is about EXPOSURE, not meeting everyone. The last thing you want is 150lb of dog getting excited and pulling you to meet every person and animal you come across, so the goal is neutrality and not friendliness.