The arrival of several players who have the best quality can help the team's overall performance and Real Madrid has done that because they move faster.
But it seems that for Barcelona there will be no significant changes for the defenders next season.
The thing is that Madrid's players are a hospital if you look at them, almost all the good ones are injured, there is no defense, there is no material to win a good championship, however they played with what they had, like Ancelotti I would have taken pure players from the quarry for defense and I would never put in those I had except for Asensio, they should change and they should put in a good defense, which I think they have already signed, in the case of Barcelona they are trusting a lot, they are sticking to Cubarsi and their defensive line betting everything on the attack, well we will see in the next season if it works for them.