Pre-season friendlies and their results dictate nothing. Even if a team loses all their matches, we can't write them off. Pre season is all about coaches finding out the right players in their starting XIs. Testing out as many players as they can. That's what preseason is all about.
If talking about Barcelona and Real Madrid specifically, they had decent preseasons each. Both teams have a decent squad to work with, especially Real. A lot of talents to browse through, and star players too. They kicked off well and might end up with 1/2 trophies in the end. Barca also trying their best to find the sweet spot, with a new gaffer in the club. La Liga should be interesting in 24/25, with Atletico also strengthening their team.
I think a have a slightly different opinion from yours concerning the prospective performance of the clubs you mentioned in this new season. Barcelona if you ask me doesn't look like the team that's found the rhythm to challenge for the league title this season. Looking at the Barcelona team and the fact that they do not have a natural winger in the left side of attack, I do not think they can challenge Real Madrid for the league title this season. There's no doubt that Barcelona is one of the most successful clubs in the league but without being sentimental, I think Atletico Madrid posseses more threat than the Catalonian club. Real Madrid won the Spanish La Liga title last season but a critical look at the team and quality of players at the club manager's disposal, I'll be extremely shocked if Real Madrid fails to retain the league title