This is an important point. He should be given time to adapt to the team completely. He is going to compete in a way more different and challenging league above all else. I'm happy for him about scoring goals already because these things would help him motivate himself for the new season in the Premier League as well. People should just be patient to see his real potential. His performance at his previous team was already amazing and I'm looking forward to seeing at least that level after some time.
Of course, even every player who has played in the Premier League will also have to adapt to his new team if they move. For example Sterling, Jesus and some other players have to be given time to adapt and that's normal.
Haaland and Nunez are two players who have good goal productivity, but I think both players have to work hard to shine in the Premier League because this competition is completely different from the competition they played last season. It will be very curious how these two players compete to be the best this season for their respective teams, I think Liverpool vs Manchester City will be even more exciting.