It's high time the club knows what they need and go for it, they can't keep signing frontlines without scanning the backlines, how these roles operates. The defenders are not fully positioned to win games, rather they keep making blunders that cost them to concede goals in league games. PSG coach, Luis Enrique should make more signings this season, in full focus on the defend and midfield, because that's where their problem originates from. PSG have missed out on big names this season, players that would have secured an easy win for the parisians have already exited the club.
I also see that problem in every season at PSG and it hasn't been resolved until this season so the advice you give is actually also more appropriate for PSG because they need to be able to focus on bringing in better players in midfield and defense. This was also revealed when PSG's front line became unproductive in scoring goals when there were no players who were good at providing passes from the back or midfield. So the PSG team must also be stronger on two lines that have not been their focus so far.
The lineup that a club must have is the balance between positions in the game, be it defense, midfield, or attack. They can't keep strengthening their attack, but they forget to strengthen the depth of the midfield and backline. They also can't focus on one position at the back, but forget about the attack. because it would also be useless if they are good at defense but they can't create goals. I have seen this problem for years in Paris Saint Germain, strangely they don't seem to realize that it is their weakness.