If you evaluate teams by their players, then Real Madrid looks stronger now, it's hard to argue with that, but the strength of a team is not always determined by that alone. If there is a team in La Liga that can stand up to Real Madrid, it is Barcelona, Atletico often falls short of competing with them. And while Real Madrid is strengthening its team, Barcelona cannot afford it due to financial problems.
No one will argue that the squad of Real Madrid is getting stronger. We take a look on the quality of Real Madrid players, they have more quality players now. With 2 new top strikers (Mbappe and Endrick), Real Madrid is expected to have better performance for the next season. However, it is true that there are many factors to determine their performance, it is not only about the quality of the players. If Ancelotti can't choose a proper strategy and fail to build the mentality of the players, Real Madrid performance may be beyond our expectation. Having many top players in the squad sometimes has a certain challenge, it is about the ego of the players. This makes them to play more individually and it will be difficult to order them playing as a solid teamwork. But I still believe that Ancelotti always knows how to deal with this possible problem.
I think both Barcelona and Atletico Madrid still can compete with Real Madrid. They are also reshaping their squads, it is very possible that they may play better with the new squads. Atletico Madrid has a new striker (Alexander Sørloth), the striker with the second highest number of goals last season. This can boost the performance of Atletico Madrid. Meanwhile Barcelona, they will be always the real competitor of Real Madrid. Even if they are in financial crisis, they still have good squad. Yamal is the most shining player in Barcelona now. This player can be one of the factors of better performance of Barcelona in the new season.