Real Madrid started better than Barcelona. However Barcelona's performance was still good actually. They just struggled about finishing up their attacks with a goal. Maybe it was a really bad luck. But we would find out about it by next week games. Real Madrid might have lost points too by the way because they had to make a comeback from a 1-0 disadvantage.
Yes, so far each team has had one match because there are some new players so they need more matches to gain cohesiveness
Real Madrid is still above Barcelona for now. With Real Madrid's composition so convincing, they are also made easier because they don't have to bother overhauling the game because most of them are players who have been in the team for a long time. While Barcelona of course must create harmony between players first.
Madrid has gone through a fairly perfect start in all competitions, although the majority still retained the squad last season but madrid was still able to maintain its consistency in winning, the cohesiveness and chemistry that had been closely intertwined between the players could of course be a strong reason for madrid current performance, but I think barcelona can also soon become a strong team if they can quickly solve their current problems, actually the many star players that are in barcelona won't be too difficult for Xavi to unite them in cohesiveness and also the style of play because basically the new players barcelona has a game that fits Xavi criteria.
Real Madrid did not make any changes to their squad. Because they are not interested in wasting money. They kept the squad unchanged from the previous season as well. And consistently performing well. If Rodrygo, Vinicius and Benzema are in form, Real Madrid will be favorites for the title again this season. As Vinicius became more experienced, his performance gradually improved. And so despite not making any changes to the squad, Real Madrid is still a strong team this season.