Osimhen is a top level player for the Turkish League. If Galatasaray wants to succeed in the European cups, they should definitely include Osimhen in their squad and they are very close to it. However, I think a Galatasaray transfer for Osimhen will have a negative impact on the player's career. Because a player like Osimhen needs to play in the premier league and success there will put him among the best in the world. I think Osimhen liked the family atmosphere in Galatasaray and he refused Napoli's training sessions at the start of the season because of this atmosphere.
Of course Galatasaray wants to achieve good results in European competitions but Osimhen already played for them last season and that did not help improve their results in any way. Now they have also added Sane to their squad and I think this will further strengthen their attack. They are working on keeping Osimhen. He fit into the team very well and scores consistently so it is clear why they want him to become their player and not just a loaned one. But for now these negotiations have stalled because they cannot agree on certain points with Napoli. But I see that Galatasaray is very persistent so I think they will be able to get him. Still I am not sure this will help Galatasaray in European competitions because one player cannot significantly influence the results of the entire team.