Yes, his decision to bring Xavi Hernandez back as coach, was one of the right decisions. Even though we know many doubt him, but he sticks with his stance. The result we can now see, it is not perfect, but there is promising progress since Xavi took charge of Barcelona. Now they look so good, many even believe this season they are strong candidates for the title.
Xavi's job to coach the Barcelona squad is not easy, because Xavi is not only required to win but also to play beautifully.
This summer, Barcelona have played 3 matches with 7 points and are third in the La Liga standings. but yes, bercelona in the hands of xavi hernandez underwent many significant changes after replacing the coaching ronal koeman last november. Currently Xavi Hernandez's squad can be said to be in quite good form from the last two matches and get perfect results.
However, La Liga has only been running for three weeks, Barcelona must remain consistent with every performance in the next match, because the strongest candidate to win La Liga is still owned by Real Madrid.
As you wrote it is just 3 weeks of La Liga, so it is still too early to say much about conditions of teams like Barcelona, because they have many new players. To see how looks Barcelona after so many transfers we need to wait for confronation with Real Madrid.