After Luis Enrique took over at PSG, we didn't really see the kind of change we expected from PSG. The team has improved since Luis Enrique took charge at PSG but the team did not buy any players during the transfer season, instead they sold a dozen players from PSG. I waited until the last day of that transfer window for a big deal for PSG but nothing happened. I don't know what Luis Enrique's plan is but if they could get some quality players in their team in that transfer window, maybe they would have had better success this season in the Champions League. The Champions League tournament requires good quality players with skills which PSG do not have at the moment and unless PSG have good quality players they will not do well in the Champions League.
They bought Neves from Benfica, but I agree that they did not make any big signings for attack, which was a usual thing for PSG before. Last season PSG also achieved quite good results without signings, and apparently Enrique decided that he could continue this season without strengthening the attack, but they lost Mbappe and this became a very noticeable setback for their attack.
PSG's performance has been stable as long as Mbappe has been at PSG but since Mbappe's move to Real Madrid, PSG's performance seems a bit erratic but they have been doing fairly well in their local league. Even with Mbappe, they wouldn't have been able to do much better in the Champions League because the Champions League is usually a very tough competition. If the team performance isn't good, one player alone can't bring results to the team. Since PSG has enough financial backing, PSG should focus on buying quality players and ensure that those players are young and talented. Buying a young player means that PSG will get good performances from that player and if they develop the player well in the future, they can sell that player to another club for a big profit.