It is very difficult for Xavi to have performed a miracle of this kind, although for me I am not a fan of Barcelona Xavi is a very good coach, and despite losing many things in some important championships, he is still a fundamental key for Barcelona. However, I think that Barcelona should continue to keep Xavi in charge, he has shown that he has full knowledge of each of his players, another thing is that they have also lacked good luck.
Xavi is a good coach for Barcelona in this time. They have found a young and talented coach who was home-grown in La Massia and is supported by fans of the club.
Xavi in management aspect has shown that he can do it very good. He brings some fresh air to their players, improve their mentality, belief and revive career of some players there, from Alba to Dembele. He convinced the club to bring Dani Alves, Traore and Aubameyang to Nou Camp. They all have contributed good things for Barcelona.
They must bind their future with Xavi if they don't want to bet with another coach and fall into crisis again. In fact they failed with Koeman before Xavi came and fixed it.