In my opinion, Osimhen and Leao are important targets. PSG may try to bring them to the team instead of Mbappe. I don't think Milan will leave Leao because he is an important part of a team with high goals. However, Osimhen can leave Napoli with a good transfer fee. I believe he will be successful in Paris, too. I think he will not be as successful as Mbappe, but he will still be good.
I agree with you because by now PSG must have identified all the players they feel will boost the performance of the team when Mbappe will leave the club, however considering the performance of Osimhen he is the right player for PSG because he is very good and strong even though he is not skillful but he knows how to utilize a scoring opportunities, so like you said even if his performance is not up to Mbappe but he will surely be an assets for PSG because I believe that a player with the kind of speed and force Osimhen has is actually suitable for PSG because they will help Osimhen improve the more because they have a very good quality players that can assist Osimhen very well, however when Osimhen leaves Napoli it will also affect the team because he has been doing really well for the club in terms of creating scoring chances and assist.