Even if money buys everything that makes sense, it will never guarantee that PSG can win the Champions League title that easily. PSG must build a squad with the best mentality and quality, but so far PSG have not been able to do that.
They have to learn from how Manchester City built their squad and mentality, so even if they spend a lot of money it will be worth it. Hiring a quality manager for many seasons like Luis Enrique can make them have the possibility of reaching the Champions League final or even winning it, but PSG tend to switch coaches easily when they fail in the Champions League.
The problem is that PSG always fails to reach the final Champion League even in the last 2 seasons their steps stopped in the last 16 obviously this is not an achievement that can be proud of, so it is normal if PSG is looking for a new manager. When compared to Manchester City clearly the achievements were different because they go to the final 2 times until they finally became champions. Actually when a team like PSG has many star players it will be more difficult to manage it, there are always obstacles related to egoism and other things.