One of the factors is that he is still young he has enough energy so he can overcome obstacles no wonder for the next few years his name will always appear on the scoreboard
Dortmund also realized this so they kept Haaland in this transfer window, btw Haaland has not been able to surpass Robert Lewandowski in the top score list.
Currently lewandowski is the bundesliga top scorer with 18 goals, while haaland has only collected 11 goals from 10 matches, actually haalaand had the opportunity to equalize goals with lewandowski this season, but the injury suffered by haalaad forced him to miss many matches, I think with his young age Haalaand will be able to become the best player in the world in the next few years, and of course it will be a big loss for Dortmund if they are not able to keep Haalaand in the transfer market, but I still think Dortmund will let Haalaand go for money.