Zidane is a great coach even though PSG was relatively late in recruiting this good coach because Mbappe was about to leave PSG, but PSG didn't appoint Zidane because Zidane decided to take a break after becoming Real Madrid coach so PSG couldn't offer him, but now it looks like Zidane has wants to return to the training chair and wants to take on a coaching role again but we also don't know which club he will manage. PSG has sufficient resources. If Zidane trains PSG then Zidane can buy the players he needs and he can create his strategy according to the capacity of his players.
No it doesn't depend on Luis Enrique only. There is a reason why teams from leagues like Portugal, Eredivisie, Ligue 1 and others almost have no chance to win the Champions League. The main reason is that these teams are not good enough and if they are in regards to the players they have and the quality they potentially can bring onto the pitch, then the teams don't get challenged enough throughout the year and are playing against far inferior teams all the time. But then out of a sudden the next opponent is called Real Madrid or Manchester City and that is when they haven't developed the tools during the season to deal with the problems that these world class teams can create for any opponent. PSG won't win the Champions League and I doubt that Enrique should be blamed for it. It's never the best idea to buy a club in a weak league, invest billions and then hope to win the Champions League.