Most likely psg didn't have any luck last season in the Champions league because they have a very strong squad but failed to advance to the Champions league final. PSG are a big team who have a pretty strong squad but they don't have the mentality to be champions yet.
Manchester city can be a big obstacle for PSG next season because Manchester city is the strongest candidate besides Real Madrid. Next season some teams from epl return to champions league like manchester united. So there is so much competition that will occur next season in the race for the ucl trophy.
PSG faced too many obstacles last season in the Champions League which ultimately made them fail to qualify for the quarter-finals after being defeated by Bayern Munich. Christophe Galtier is a coach who is doubtful for bringing great success to PSG in the Champions League, that is far greater than several previous coaches such as Carlo Ancelotti, Laurent Blanc, Unai Emery, Thomas Tuchel and Mauricio Pochettino.
For next season PSG have signed a contract with their new coach, Luis Enrique. He may not be any better than the big names of Europe's top coaches at the moment, but Enrique has a good track record with Barcelona a few seasons ago. He can repeat his success at PSG if he gets the support he deserves, but of course he needs time and a gradual adjustment.