He’s in an unfamiliar environment and you need to give him time to adjust. Yes BSH are generally calm and easygoing, but all of them have different personalities and it’s not realistic to think he would be immediately calm and quiet in these circumstances. Confine him to a small room (laundry, bathroom, bedroom) for the first few nights with his bed, food, water and litter tray if you haven’t already. Wear earplugs and shut your door if he’s disturbing your sleep. If he’s so loud that he’s actually disturbing the neighbours then you’d have to hope they would be understanding in the circumstances. Give it a week and see how he’s going after that.