PSG have signed two players so far and these are Vitinha and Nuno Mendes. They have spent 80 million euros in total but I don't have any doubt that they have much more money left in their budget. However they aren't rushing their transfers now. We still haven't seen a big move from them. Maybe it would be nice for them to consolidate the team more with big transfers now. However their main problem was with the management and they have made their move for that as well. Time will tell how they will play in the CL this time.
I'm not sure PSG will make a high transaction because basically PSG already has a lot of players with expensive salaries, this doesn't mean PSG don't have the money to buy more expensive players. Because they are also considering financial fair play and because of that, PSG so far have not been rumored to be bringing in expensive players, perhaps the most feasible reason is that they no longer need the player. Think of it as before about the Ronaldo rumors, basically PSG have the ability to sign Ronaldo but they rejected it on the pretext of not needing him because there are already many great players in that position in their squad.
PSG current squad is very good in all respects, maybe they just need to bring in a few players who play as defenders and that has been done as rumors will bring De Ligt from Juventus but overall they already have a qualified squad so they don't look too active in buying players in this transfer market.
and of course money is not an excuse for them not to make a lot of signings in this transfer window, because financially PSG are very good, there's no doubting that.