It's partially character but it's also the way politics work within football and status is amassed throughout your career.
Haaland cannot create his own chances as much as Mbappe does. Creative attackers generally commend more status within a team.
Also, don't forget Haaland at 19 was playing in Norway while Mbappe was already a superstar who had won the World cup at 19.
Even then, Mbappe came to PSG as the 'understudy' of Neymar. Throughout the years he has received the status of top dog at PSG because of his performances, his age (in relation to Messi's and Neymars age) and the threat of leaving to whichever club he desires.
Who knows, in a few years Haaland might be as much of dick as Mbappe.