Messi leaving Barcelona gives them a chance to steady the ship, although it might not be enough. They are probably still short of what they need, and I doubt Aguero and Depay are going there to play for nothing.
A player like Pedri represents a new future for Barcelona. If I understand his situation, he is still on a low wage, but has been promised a new deal in keeping with his growing status, as soon as they can sort out the accounts.
It is possible that they can’t quite get there, and so Pedri will feel slighted as he watches other players who are not much better, and perhaps even less important to the club, earn 5x what he does.
I suppose what I’m saying is there is an outside chance that an opportunistic signing like this could present itself at the end of the window. Mikey Edwards will be all over it if there’s any chance.