Price going down
His personality is nothing like Zlatan's so I'm not sure he'll be one to keep hopping between clubs, but talking about that, if he want to play in the PL first then joining Man City and staying there until Pep leaves to hop to Barca or Real Madrid would be the move for them.
Paco,Aubameyang,Jovic,Haller,Rebic,Werner,Havertz,Modeste (25 goals 2016/17),Chicarito,Drmic,Mandzukic were players that scored about 20 goals in Bundesliga.
They all flooped in big clubs or didn't even make it to top clubs in the world. Haaland might be one of those. But again he scores like crazy in CL.
I will not be surprised if he is not even good as it seems for now.