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.
They don't seem to be signing many players for this season because it's clear that the arrivals of Vitinha and Nuno Mendes and Danilo Pereira have also taken a lot of their money, not to mention the extension of Mbappe's contract which is indeed an astonishing one in my opinion.
As for the problem of the Champions League, their target is always there, but I have seen some news that the PSG officials will not be too ambitious with the Champions League in Galtier's first season.