I don't know what will happen with PSG in future but at the moment we know that they usually get negative net in finance in many seasons. That is not good for them to unable to earn income from sports itself and rely on their owner group.
Real Madrid use leverages too but they are one of best clubs in aspect of earning money from football. They are one of most successful clubs in history and PSG are too small to compare with Real Madrid.
I don't know for sure about finances in more detail. But bringing in some star players is also a strategy for marketing. The purchase of Messi and other stars is not without purpose. I read the local media that messi's purchase brought 700 million euros in income. Money from sponsors gets an increase of 13%. Jersey sales and spectator tickets also have a large income. According to sources I've read they sold 1 million jerseys last season. Indeed, when compared to Madrid, of course, PSG is a new club that has not been heard for a long time. They achieved success because investors came.
SourceSigning star players, especially those who are a little old, is actually not intended to strengthen the existing squad (although many of them can improve team performance) but are nothing but profitable from a business perspective, usually clubs are willing to pay dearly by reviewing the capacity and popularity of these players so that by so at least it can increase the popularity and also the club's income from jersey sales or sponsorships, I think that's why PSG used to dare to sign Messi at a pretty fantastic price considering its extraordinary fans today, the same thing Juventus did when they signed Ronaldo from Madrid with the reason of wanting to get the champions league trophy, even though Juventus were constantly blasphemed for buying Ronaldo at a high price but were unable to bring Juventus to win the champions league, but I think instead juventus won in terms of financial benefits while signing Ronaldo at that time.