Personally, I don’t think Barcelona have time to wait a few years. Changes in football happen very quickly and if you can’t keep up with those changes, then you fall away as a relevant factor.
Top players want to play in clubs that guarantee them trophies and victories, and they can also pay well. Personally, if I were a top player and I got an offer from Barcelona, a club that can no longer guarantee trophies and money, and Newcastle that will soon be able to guarantee both trophies and money, I know which club I would choose. It has already happened in football that some clubs that used to be greats and European champions, such as HSV or Nottingham Forest, later fail and become irrelevant.
Barcelona don't have much time to fix their catastrophic financial situation and avoid such a scenario.
Very rarely, serious changes occur without consequences and in a short time. You can talk as much as you like about whether Barcelona has time to transform or not, but the fact remains that in its current state, Barcelona is unlikely to be able to claim the title of the winner of the Champions League.