If there was no Xavi, maybe Barcelona would have fallen even deeper. We can see that when Xavi first arrived, he handled the Barcelona team which was already in a very bad state with all the problems they were facing, but slowly Xavi built this team with adequate finances provided by the team management.
It sounds very strange if Xavi is blamed for the decline in Barcelona's performance this season, the team management must actually be responsible because they did not provide full support for Xavi to build this team.
At the end of the season Xavi has decided to leave the team and I think that will make Barcelona very difficult and I think with their new coach next season they will not have a large percentage to be better than this season, I am very pessimistic about that.
Xavi took this team from basically "about to crash" to a level where it can sustain itself. Can they get out of their 1.2 billion dollar reported debt? Well they are a football club, and they sold their future revenues as well so not like that is going to mean something, but if they want to, they can get rid of half of their debt literally this summer. Would it be worth it?
I do not think so, but it is really not that impossible. How? Selling off players, they can sell Gavi, Pedri, Yamal, De Jong, Araujo, Raphinha, Kounde, Balde, Roque and more. That would mean at least 500 million in just one summer, or at least 500 million euro worth of assets on sale basically and could sell slowly with time because finding teams to pay that much may take some time. In the end, yes they do have a big debt, but they also have assets to pay half of it.