PSG at the moment have an enviable squad depth, all they need is to enhance it for next season due to how expectations on them would be very high as defending champions in the champions league. Imho, Gavi is a quality player but he doesn't fit into the PSG kind of football with how prone he is to injuries he can't be reliable to be consistent in a season. What PSG needs a midfielder that is void of such injury problems and Gavi isn't that player.
PSG has a good squad depth that Luis Enrique can possibly use to retain the French Ligue 1 title and compete in the UEFA Champions League competition. Luis Enrique just needs to add a few players to his squad so that if PSG is hit with an injury crisis, there will always be good players on the bench for Luis Enrique to use at PSG, and PSG will not struggle the way Real Madrid did this season when they were hit with an injury crisis.