You're right, Xavi has really brought his players together at Barcelona this season. When the strikers get stuck, Pedri or Gavi perform well and make Barcelona win with their goals, as well as Dembele or Raphinha.
Xavi helped Dembele to revise his career and I don't think without Xavi, Dembele could come back to his best like this. Years since his transfer from Dortmund to Barcelona, only under Xavi time, he has shown that he is a player who can play at world class level, in Barcelona and in France. Good performance in Barcelona brings Dembele back to France squad.
You are right too that Xavi reunited Barcelona so well and make them stronger as a whole team.
Tactically, Barcelona has good performance to record many chances to score. The 42 goals they have scored in 20 matches is proof that they are the most productive team in La Liga at the moment. Besides, Barcelona's defense also helped a lot, they only conceded 7 goals in 20 matches. No other team has this kind of defensive power in La Liga, only Barcelona leads the statistical average.
I don't surprise with their ability to score goals but surprised about their defense. 7 goals after 20 matches is a very impressive stats for their defense system and it makes more sense as nowadays Barcelona are not dominating La Liga like years ago with Xavi in their midfield.