It was a very good decision by Mbappe by forcing his way out to seek a better challenge in order to win more trophies. He has served the club well and i believe it was time for them to depart and this is something PSG should understand and move past him, they need to learn to play without certain players and understand that no player will be with them forever. They should start signing players to replace the lost players even though they can’t perfectly fill their void yet.
A player with a qualified talent must have a wise choice and no wonder Kylian Mbappe chooses to leave PSG in order to have a better future with the right club and it makes no sense to stand up with a rich club but in terms of career can not provide a prestigious experience in the Champions League competition.
PSG as the wealthiest club in league 1, shouldn't be desperate to lose a credible player because the club has a lot of money and can bring a professional player to replace Mbappe's position. Sooner or later PSG will definitely bring professional players that we didn't think of before and maybe players like Osimhen could join PSG.
Despite the dominance in France and the wealth of PSG, they've not been able to achieve their Champions League dreams. This is why they are trying their best to buy huge names in football, but still do not have that luck yet. I think they should look beyond the buying of big names but completely structure the team in a short space of time, and with a viable coach. They often rely on some sectional players where almost all the players should be trusted to deliver. Take Man City for instance, you will hardly see a player there that is not so fitting for the spot he plays, that's what we call a good team and not having it strong somewhere but having it weak or manageable elsewhere. This arrangement only puts pressure on their key stars and in that condition, they may not be able to deliver at best.
Now, good names like Messi, Mbappe, Di Maria, Neymar etc who were bought with huge amounts a few years ago have left, which can only mean that money and their current style will not get them their desire. Also, you are right about the sorting for big players by luring them with big money and are willing to splash €200m on both Victor Osimhen and Khvicha Kvaratskhelia. Victor Osimhen may still be tempted even though he prefers to play in the premier league but Napoli has maintained their unwillingness for Khvicha Kvaratskhelia regardless of the offer.