Returning Lukaku to Serie A is like feeding an old lion a tasty steak. Despite playing in other leagues, he thrives in Serie A. Napoli grabbing him with Osimhen already there is powerful. Think of it as a tag team of animals with diverse skills ready to crush opponents. Lukaku now plays with finesse and expertise, not speed. This move changes Napoli's game
Osimhen's worth has dropped, but who cares? The transfer market is a rollercoaster. Players go up, they go down, it's the circle of life, bro. The guy is still a beast on the field and will kill it wherever he goes
Strikers with playing style depends on physical strength like Lukaku and Osimhen usually have more difficulty when they get older and their bodies become weaker. Playing styles of Osimhen and Lukaku are easy for defenders to guess and make their defensive plans. The match between Italy and Belgium in Euro 2020 is an example when Chiellini and Bonucci controlled Lukaku very well with their defensive experience.
Lukaku's speed and playing style does not match with Premier League but in Serie A, with lower match intensity, Lukaku can adapt well and play better.
Osimhen used to be a most wanted striker in Europe 2 seasons ago but after the last season, a failure of Napoli to defend their Scudetto and not too good individual performance of Osimhen, his transfer price drops a lot.