More than well known... It's practically established at this point. 9/10 Pep players look unreal their second year. They become telepathic with their team and the system.
Haaland at this level is a great sign of things to come. He said that he watched City religiously, imagining himself at the end of the tactics, and so it's no surprise to see him flourishing. He will get even better with that daily exposure to his new environment.