I think they shouldn't rush into the transfer. Mbappe is an important player, but his absence can be filled by a player somehow. Here, PSG observers and technical staff will have to work overtime to choose the best. Mbappe is gone, but the next name will have to look no further. A difficult period begins for PSG. They should select the best player and add them to the team and play better next year to lift the UCL cup, which is their main goal.
Losing Mbappe will certainly not make PSG devastated because as a team they still have the opportunity to bring in other reliable players, but losing Mbappe will actually make their performance decline a little because it is difficult to get a complete player like Mbappe, currently of course Madrid is very benefited by getting Mbappe for free and obviously it should be a regret for PSG because they losing player with a price tag of almost 200 million euros at the moment, PSG is currently of course busy looking for a player who can indeed replace Mbappe role in their front line next season and seeing the limited strikers that are available, of course PSG will have to work hard and need time to get him.
PSG is the richest team in the world and maybe buying players at a high price will not be a problem for them if it suits their needs next season, but I think in addition to focusing on finding a replacement for Mbappe, of course PSG also has to think about the depth of the squad they have, including to add some new players who can indeed strengthen their midfield and also their defense next seasons.