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.
Their idea has obviously been to win the games by scoring three more goals than the opponent, so be it 4-1 or 5-2, it doesn't matter. But the thing is that this works against weak or average teams, but it doesn't work in the Champions League and that's where they tried it again and again with the same strategy, losing the games mostly because of problems they had already encountered before.
If the line-up includes Mbappe, Messi and Neymar, it should immediately be noted that this comes at a cost. Having one player in the team who doesn't support the defense can be ok, Having two of them is already bad for the team's balance and having three of them, well... That is too much.
Now PSG had this short period of time when everyone thought they would win every game with ease because of their attack line, but it wasn't the case. I am really curious to see what their vision is for the mid-term now.