For now, Real Madrid is predicted to return easily to defend the title and dominate La Liga. However, it is also possible that Barcelona will perform beyond our predictions, maybe they will play much better with their new coach, Hansi Flick. Comparing the composition of players from the two big clubs in La Liga, in my opinion Barcelona also still has a good composition of players, it's just that when compared with Real Madrid, it's clear that Real Madrid is still better.
Talking about the experience of the players at these two clubs, in my opinion they are not much different in terms of experience, but again Real Madrid could perhaps be said to have players whose experience is more evenly distributed than Barcelona. What is highlighted is the problem of the players' mentality. I see Real Madrid being more successful in forming the mentality of the players they currently have. Even though they are still young, they have a very good mentality.
Who do you consider to be a less experienced player in Barcelona, maybe Lewandovka, or Gundogan, or Ter Stegen? Every team has enough young and experienced players, it’s just that Barcelona last season faced the problem of a large number of injured players and the absence of Ter Stegan was especially acute when Baocelona conceded too many, this became decisive. But I can’t say that Barcelona is much weaker than Real. Perhaps Flick will cope with his responsibilities as well as Xavi, and given that he is a more experienced coach, he can also respond more steadfastly to criticism than Xavi did.
All three players you mentioned are not too bad for the team, Lewandowski and Gudogan are top class player who have been in successful clubs and I feel they still retain this winning mentality which we are yet to see the best of them at Barcelona. A new season should be a good start for Barcelona despite having lesser possibility of winning La Liga, they will have a good season, runner up with no much point difference with Madrid.