Galatasaray are interested in keeping Osimhen because Osimhen is a great player but Osimhen wants to play for a big club in Europe and perform his best there. Last season he had a big chance to move to a top club in the English Premier League and big clubs were ready to pay big money for him but at that time his club did not help him so he had to move to another league outside Europe. When the transfer market opened this season there were rumors that either Manchester United or Liverpool would buy this player but as time goes on it seems that maybe his dream of moving to a big club in the English Premier League will not come true this season and he may have to stay at his current club for another season. The longer he stays at a club outside Europe his market value will gradually decrease.
Osimhen has proven himself to be a much-needed player at Galatasaray. He even finished as the top scorer in the Turkish league last season. So it's no surprise that Galatasaray has now agreed to pay Osimhen's release clause to acquire him. However, Galatasaray can't pay the full price all at once due to regulatory issues or something. However, an agreement has reportedly been reached regarding installment payments, which will be finalized at the end of the season. So I think Osimhen will definitely be joining Galatasaray soon.
Osimhen's dream is to play in a bigger league like the Premier League, and in the past few seasons, he received offers from English clubs and Ligue 1 side PSG. However, Napoli rejected these offers, leaving Osimhen to stay and then be loaned to Galatasaray. Fortunately, he's comfortable there, and now he's keen to join the club.
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.